PSLE
Emma had two ribbons of the same length. She cut the first ribbon into equal parts of length 50 cm and to each part she tied 2 black paper cranes. After that, she cut the second ribbon into equal parts of length 60 cm and to each part she tied 3 gold paper cranes. When she finished tying, she counted that there were 15 more gold paper cranes than black paper cranes. How many paper cranes were there altogether?

	First ribbon	Second ribbon	Difference	Total
Length of each part	50 cm	60 cm
Number of balloons tied to each part	2 black balloons	3 gold balloons
LCM	300 cm	300 cm
Number of equal parts	300 ÷ 50 = 6	300 ÷ 60 = 5
Number of balloons for each ribbon per set	6 x 2 = 12	3 x 5 = 15	15 - 12 = 3	12 + 15 = 27

LCM of 50 and 60 = 300

Number of sets of 2 black paper cranes in a length of 300 cm
= 300 ÷ 50
= 6

Number of black paper cranes in a length of 300 cm
= 6 x 2
= 12

Number of sets of 3 gold paper cranes in a length of 300 cm
= 300 ÷ 60
= 5

Number of gold paper cranes in a length of 300 cm
= 5 x 3
= 15

Extra number of gold paper cranes in a length of 300 cm
= 15 - 12
= 3

Number of sets of paper cranes
= 15 ÷ 3
= 5

Total number of paper cranes in one set of 300 cm of black balloons and one set of 300 cm of gold balloons
= 12 + 15
= 27

Total number of paper cranes of the two ribbons
= 5 x 27
= 135

Answer(s): 135