Day 29 of 60 · Wed 28 Oct · Daily workbook · CAT in 32 days

Day 29: Number Systems + Arrangements Set + Culture & Society RC

Day 29 of the free ThinkCAT 60-day CAT challenge: 5 number systems questions and 3 spaced-review QA questions, a full arrangements DILR set (5 questions), a culture & society RC passage (4 questions), plus para summary and para jumbles. Every question is a real CAT PYQ.

QA · 8
DILR · 5
VARC · 6
40 minutes
Real CAT questions

Concept card

Number Systems

Core formulas

N = pᵃqᵇrᶜ ⇒ number of factors = (a + 1)(b + 1)(c + 1)
HCF × LCM = product of the numbers (two numbers only)
Same remainder r on dividing by a, b, c ⇒ N = k·LCM(a, b, c) + r
Trailing zeros of n! = ⌊n/5⌋ + ⌊n/25⌋ + ⌊n/125⌋ + …

60-second shortcut · Factor count in one line

360 = 2³ × 3² × 5 ⇒ 4 × 3 × 2 = 24 factors; odd factors (drop the 2s) = 3 × 2 = 6.

Trap box

Looks like: Factors of 2³ × 3² = 3 × 2 = 6Actually: Add 1 to each exponent: 4 × 3 = 12
Looks like: Zeros in 100! = 100/5 = 20Actually: Add ⌊100/25⌋ too: 24

From the free Number Systems Formula Sheet (PDF).

What's in Day 29

QA: Number Systems (5) + 3 spaced-review questions
DILR: Arrangements set, 5 questions
RC: Culture & Society passage
VA: Para Summary, Para Jumbles

Year, slot and question number for each question appear with the answer key after you submit.

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