PSLE
Joelle had two streamers of the same length. She cut the first streamer into equal parts of length 80 cm and to each part she tied 2 black paper cranes. After that, she cut the second streamer into equal parts of length 90 cm and to each part she tied 5 purple paper cranes. When she finished tying, she counted that there were 110 more purple paper cranes than black paper cranes. How many paper cranes were there altogether?

	First streamer	Second streamer	Difference	Total
Length of each part	80 cm	90 cm
Number of balloons tied to each part	2 black balloons	5 purple balloons
LCM	720 cm	720 cm
Number of equal parts	720 ÷ 80 = 9	720 ÷ 90 = 8
Number of balloons for each streamer per set	9 x 2 = 18	5 x 8 = 40	40 - 18 = 22	18 + 40 = 58

LCM of 80 and 90 = 720

Number of sets of 2 black paper cranes in a length of 720 cm
= 720 ÷ 80
= 9

Number of black paper cranes in a length of 720 cm
= 9 x 2
= 18

Number of sets of 5 purple paper cranes in a length of 720 cm
= 720 ÷ 90
= 8

Number of purple paper cranes in a length of 720 cm
= 8 x 5
= 40

Extra number of purple paper cranes in a length of 720 cm
= 40 - 18
= 22

Number of sets of paper cranes
= 110 ÷ 22
= 5

Total number of paper cranes in one set of 720 cm of black balloons and one set of 720 cm of purple balloons
= 18 + 40
= 58

Total number of paper cranes of the two streamers
= 5 x 58
= 290

Answer(s): 290