The task is to generate the correct answer for a given math problem.

Ex Input:
Problem: the average of first 5 multiples of 5 is

Ex Output:
1


Ex Input:
Problem: the number of singles that a baseball player hit increased 10 percent from her first season to her second season , and the number of doubles that she hit in the same time period decreased by 1 percent . if the total number of singles and doubles that she hit increased 3 percent from her first season to her second season , what is the ratio of the number of singles she hit in her first season to the number of doubles she hit in her first season ?

Ex Output:
4 : 7


Ex Input:
Problem: robert ' s salary was increased by 50 % and subsequently decreased by 10 % . how much percentage does he gain ?

Ex Output:

15 %