This isn't hard at all! The 6 dolls she brought are 20% of her entire collection, right? All you have to do is multiply the 20% by 5 so you can get the amount of dolls to 100%, so
6 x 5 = 30
That's how many dolls there should be.
Her box is 12 inches tall.
-Because if you multiply 13 × 5, you get 65 (this is the base) then you work backwards and divide 780 by 65 (780 ÷ 65). Therefore your answer is 12 inches
Go to the third pic for your answer. I got problem 4 wrong but it shows the correct answer.