Answer:
Step-by-step explanation:

.
Rates:
Ryan: 1 hole per 5 hours
Castel: 1 hole per 6 hours
.
Let x = time if working together
then
x(1/5 + 1/6) = 1
x(6 + 5) = 30
11x = 30
x = 30/11
x = 2.7273 hours
or
x = 2 hours and 44 minutes
When Ivan divides his coins into groups of 2 nickels and 1 quarter, worth $0.35, he find that he has $8.75/$0.35 = 25 such groups.
Ivan has 25 quarters and 50 nickels.