PSLE
Diana had two streamers of the same length. She cut the first streamer into equal parts of length 25 cm and to each part she tied 2 pink paper cranes. After that, she cut the second streamer into equal parts of length 40 cm and to each part she tied 4 yellow paper cranes. When she finished tying, she counted that there were 20 more yellow paper cranes than pink paper cranes. How many paper cranes were there altogether?

	First streamer	Second streamer	Difference	Total
Length of each part	25 cm	40 cm
Number of balloons tied to each part	2 pink balloons	4 yellow balloons
LCM	200 cm	200 cm
Number of equal parts	200 ÷ 25 = 8	200 ÷ 40 = 5
Number of balloons for each streamer per set	8 x 2 = 16	4 x 5 = 20	20 - 16 = 4	16 + 20 = 36

LCM of 25 and 40 = 200

Number of sets of 2 pink paper cranes in a length of 200 cm
= 200 ÷ 25
= 8

Number of pink paper cranes in a length of 200 cm
= 8 x 2
= 16

Number of sets of 4 yellow paper cranes in a length of 200 cm
= 200 ÷ 40
= 5

Number of yellow paper cranes in a length of 200 cm
= 5 x 4
= 20

Extra number of yellow paper cranes in a length of 200 cm
= 20 - 16
= 4

Number of sets of paper cranes
= 20 ÷ 4
= 5

Total number of paper cranes in one set of 200 cm of pink balloons and one set of 200 cm of yellow balloons
= 16 + 20
= 36

Total number of paper cranes of the two streamers
= 5 x 36
= 180

Answer(s): 180