First you would start getting the denominators to the same number and you could do this by multiplying 9/10 by 4, and 7/8 by 5 to get the denominators to 40 and when you add the fractions you get 71/40 so the answer would be D. About 2
The length is 10
The width is 4
4 + 6 = 10
4 x 10 = 40
8 gorrilas
Explanation:
The ratio of monkeys to gorrila = 5:2
This means there are 5 monkeys for every 2 gorrilas
when there are 20 monkeys,
let the number of gorrilas = x
5 monkeys = 2 gorrilas
20 monkeys = x
cross multiply:
5(x) = 20(2)
5x = 40
divide both sides by 5:
5x/5 = 40/5
x = 8
Hence, if there were 20 monkeys, we would have 8 gorrilas.