You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: Rs. 6000 is lent out in two parts. One part is lent at 5% p.a simple interest and the other is lent at 10% p.a simple interest. The total interest at the end of one year was Rs. 450. Find the ratio of the amounts lent at the lower rate and higher rate of interest?

 Option A: 5:1

 Option B: 5:5

 Option C: 5:8

 Option D: 5:4

 Option E: 5:2
Option B

Question: The number of arrangements that can be made with the letters of the word COPY so that the vowels occupy the even places?

 Option A: 6

 Option B: 144

 Option C: 777

 Option D: 992

 Option E: 221
Option A

Question: On a certain farm the ratio of horses to cows is 3:1. If the farm were to sell 15 horses and buy 15 cows, the ratio of horses to cows would then be 5:3. After the transaction, how many more horses than cows would the farm own?

 Option A: 20

 Option B: 30

 Option C: 40

 Option D: 50

 Option E: 60

Option B