GMAT Divisibility: If k/n= 81.2, what is the value of n?
Question
When the positive integer k is divided by the positive integer n, the remainder is 11. If k/n= 81.2, what is the value of n?
- 9
- 20
- 55
- 70
- 81
Topics: divisibility, remainders, decimals
Solution
Step 1
We translate the statement about the remainder when k is divided by n into an equation using a quotient q and remainder r.
k = n × q + 11
Step 2
We interpret the decimal result of the division to identify its integer part (the quotient) and fractional part (the remainder over the divisor).
k/n = 81.2 = 81 + 0.2
Step 3
We convert the fractional part 0.2 into a common fraction. This will match the form remainder over divisor.
0.2 = 2/10 = 1/5
Step 4
We set the fraction representing the remainder over the divisor equal to 1/5 and solve for n.
11/n = 1/5 n = 11 × 5 = 55
Answer
55 (C)
