Percentages
Frequency 11% · 5 formulas- Percent to decimal:
x% = x / 100 - Increase by x%:
New = Old x (1 + x/100) - Decrease by x%:
New = Old x (1 - x/100) - Percent change:
((New - Old) / Old) x 100 - Successive percent:
Net = a + b + (ab/100)
Ranked by frequency in TCS NQT, Accenture Cognitive, Infosys SP, and Wipro Elite drives across January to May 2026. Each topic links to a deep-dive with solved questions and the typical drive context. The long tail of CAT-style formulas is not included, this is what actually shows up.
Frequency percentages are derived from a sample of 12 drive recaps, January to May 2026, tracked via verified candidate threads on r/developersIndia and PrepInsta. Full method lives at the methodology page.
Read this table first. Spending equal time on every topic is the wrong allocation, time-bound prep should index on the high-frequency rows.
| Topic | Drive frequency | Formula count | Deep dive |
|---|---|---|---|
| Percentages | 11% | 5 | Open topic page |
| Time, Speed, and Distance | 9% | 8 | Open topic page |
| Time and Work | 9% | 5 | Open topic page |
| Profit and Loss | 8% | 7 | Open topic page |
| Ratio and Proportion | 7% | 6 | Open topic page |
| Averages | 6% | 5 | Open topic page |
| Simple Interest | 5% | 4 | Open topic page |
| Compound Interest | 5% | 5 | Open topic page |
| Number System | 5% | 7 | Open topic page |
| Mensuration | 5% | 9 | Open topic page |
| Ages | 4% | 4 | In review |
| HCF and LCM | 4% | 3 | Open topic page |
| Permutation and Combination | 4% | 5 | Open topic page |
| Probability | 3% | 5 | Open topic page |
| Mixtures and Alligations | 3% | 2 | Open topic page |
| Pipes and Cisterns | 3% | 3 | Open topic page |
| Boats and Streams | 2% | 4 | Open topic page |
| Inequalities | 2% | 3 | Open topic page |
Grouped by topic, each block links to a question bank with 20-plus solved examples. Bookmark this page, the formulas are the floor, the linked drills are the work.
x% = x / 100New = Old x (1 + x/100)New = Old x (1 - x/100)((New - Old) / Old) x 100Net = a + b + (ab/100)Distance / TimeSpeed x Timex km/hr = x x (5/18) m/s(2 x A x B) / (A + B)|A - B|A + BTime = L / SpeedTime = (L_train + L_platform) / Speed1/T = 1/A + 1/BT = (A x B) / (A + B)(M1 x D1) / W1 = (M2 x D2) / W2Eff_A : Eff_B = T_B : T_A1/T = 1/F1 + 1/F2 - 1/DrainSP - CPCP - SP(Profit / CP) x 100(Loss / CP) x 100SP = CP x (1 + profit%/100)MP - SPNet = 1 - (1-a)(1-b)a : b = a/bx = sqrt(a x b)If a/b = c/d then (a+b)/b = (c+d)/dIf a/b = c/d then (a-b)/b = (c-d)/dx = k x y for constant kx x y = kSum / Count(Old sum + new value) / (Old count + 1)(w1 x x1 + w2 x x2 + ...) / (w1 + w2 + ...)(N + 1) / 2(First + Last) / 2SI = (P x R x T) / 100A = P + SIP = (SI x 100) / (R x T)T = (SI x 100) / (P x R)A = P x (1 + R/100)^TCI = A - PA = P x (1 + R/200)^(2T)A = P x (1 + R/400)^(4T)Diff = P x (R/100)^2N x (N + 1) / 2N x (N+1) x (2N+1) / 6[N x (N + 1) / 2]^2n/2 x (2a + (n-1)d)a x (r^n - 1) / (r - 1) for r != 1Digit sum divisible by 3Alternating sum divisible by 11L x B0.5 x base x heightpi x r^22 x pi x rL x B x Ha^3pi x r^2 x h(4/3) x pi x r^3(1/3) x pi x r^2 x hPresent age + x yearsPresent age - x years(A + t) / (B + t) = given ratioSum stays constant only at one moment, drifts as years passHCF(a, b) x LCM(a, b) = a x bHCF(num) / LCM(den)LCM(num) / HCF(den)n! = n x (n-1) x ... x 1nPr = n! / (n - r)!nCr = n! / (r! x (n - r)!)nCr = nC(n-r)(n - 1)!P(E) = favorable / totalP(not E) = 1 - P(E)P(A and B) = P(A) x P(B)P(A or B) = P(A) + P(B)P(A given B) = P(A and B) / P(B)(Cheap : Dear) = (Dear price - Mean) : (Mean - Cheap price)Final = Initial x (1 - x/V)^n1/T = 1/F - 1/D1/T = 1/F1 + 1/F2 + ...Time = V / Net drain rateu + vu - v(Downstream + Upstream) / 2(Downstream - Upstream) / 2AM >= GM for non-negative reals|a + b| <= |a| + |b|(sum a x b)^2 <= (sum a^2)(sum b^2)Across 12 recent drive recaps, 90 formulas grouped across 18 topics covered 92 percent of solvable quant questions on TCS NQT, Accenture Cognitive, Infosys SP, and Wipro Elite. The long tail of 200-plus formulas typically tested in CAT and competitive exams does not transfer here, IT-services drives stay within a known frequency band.
Time-Speed-Distance and Time-Work together account for roughly 18 percent of quant questions on tier-1 IT-services drives, based on a sample of 12 drive recaps from January to May 2026. Percentages, Ratios, and Profit-Loss together add another 22 percent. Number System and Averages round out the high-frequency group.
No. Formulas are necessary but not sufficient. TCS NQT 2026 expects you to apply formulas under a per-section time pressure of roughly 90 seconds per question. Accenture's cognitive section adds Para Jumbles and critical reasoning, which formulas do not solve. Practice with the linked topic deep-dives, not just rote learning.
Each formula on this hub links to a topic deep-dive with 20-plus solved questions and the typical drive context. The order is by 2026 drive frequency, not textbook chapter order. Repeat-failure formulas are flagged based on candidate mistakes from r/developersIndia threads, May 2026 set.
Revise in three passes. First pass, read all 90 formulas once. Second pass, drill the top 30 high-frequency formulas using the linked topic articles. Third pass, take a full mock test and only revisit formulas you missed. The mock-test loops live at the Placement Practice page and at the topic-level pages.
Frequency percentages come from a sample of 12 drive recaps, tracked January through May 2026 across TCS NQT, Accenture Cognitive, Infosys SP, Wipro Elite, and Cognizant GenC. Each recap is sourced from at least two verified candidate threads on r/developersIndia or PrepInsta. When a new pattern emerges, this hub updates within 72 hours. Source list and methodology are at the methodology page.
Maintained by Aditya Sharma. Topics: 18. Formulas: 90. Linked topic deep-dives: 17.