The zoo has lions, giraffes, and gorillas. 2/5 of the animals are lions and 3/10 of the animals are giraffes. What percentage are gorillas?

7/10

2/5+3/10=7/10

7/10 is not possible ....

2/5 or 40% are lions
3/10 or 30% are giraffes

leaving 30% for gorillas

1 - 4/10 - 3/10 = 3/10 = 30/100= 30%

To find the percentage of gorillas at the zoo, we need to determine the fraction of animals that are gorillas and then convert it into a percentage.

Let's start by finding the fraction of gorillas at the zoo. We know that the sum of the fractions of lions and giraffes is 2/5 + 3/10, which can be simplified as a common denominator:

2/5 + 3/10 = 4/10 + 3/10 = 7/10

So, 7/10 of the animals at the zoo are either lions or giraffes. To find the fraction of gorillas, we need to subtract this fraction from 1 (since the fractions together should make up the whole).

1 - 7/10 = 10/10 - 7/10 = 3/10

Therefore, 3/10 of the animals are gorillas.

To convert this fraction into a percentage, we can multiply it by 100:

(3/10) * 100 = 30%

Hence, 30% of the animals at the zoo are gorillas.