Determine the range of the prime factors of B, where B = 420.
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how much time should this take to solve?
pls explain more?
just posted another explanation
thanks, this one was quick. prime factors of 420 are easy to spot.
wait, is 'range' here the difference between the biggest and smallest prime factor? i almost just listed them and picked wrong lol
yeah range means max minus min. just find the prime factors and subtract the smallest from the largest.
i got the factors but then second-guessed myself on the last step. the wording 'range of the prime factors' tripped me up a bit.
What it tests
Your command of divisibility, primes, factors, parity, and how the GMAT tests properties of integers.
Common trap
Forgetting that 1 is not prime, that 0 is divisible by every integer, or that negative numbers flip your assumptions.