Question

fix the pronoun error (if one exists).
rafiki jumped on all of the mattresses to test how bouncy it was.
submit answer
show hint
report a problem

Explanation:

The pronoun "it" is singular, but it refers to the plural noun "mattresses". We need to use the plural pronoun "they" to match the plural antecedent.

Answer:

Rafiki jumped on all of the mattresses to test how bouncy they was.
Wait, correction: The verb also needs to agree with the plural pronoun. The correct sentence is: Rafiki jumped on all of the mattresses to test how bouncy they were.