Yoko bought pieces of paper to make 3 lanterns. She used ¹₆ of the pieces of paper on the first lantern. She used 21 more pieces of paper on the second lantern than the first lantern. She used the remaining 39 pieces of paper on the last lantern. How many pieces of papers did she buy?
Number of pieces of paper used to make the first lantern = 1 u
Number of pieces of paper used to make the second lantern = 1 u + 21
Number of pieces of paper used to make the third lantern = 39

Total number of pieces of paper used to make the lanterns = 6 u

6 u = 1 u + 1 u + 21 + 39
6 u - 1 u - 1 u = 21 + 39
4 u = 60

1 u = 60 ÷ 4 = 15

Total number of pieces of paper that Yoko bought
= 6 u
= 6 x 15
= 90

Answer(s): 90