Please help asap! Correct answer gets brainliest

Answer:
C, 35 yellow books
Step-by-step explanation:
There are 10 books in total
if 3 of them is equal to 21, then one book in the picture is worth 7 books
5 yellow books can be seen thus 7x5=35
Answer:
C. 35 yellow books
Step-by-step explanation:
Let u be 1 unit.
3u = 21
u = 21÷3
=7
5u = 7×5
= 35