PSLE
Jade had two ribbons of the same length. She cut the first ribbon into equal parts of length 40 cm and to each part she tied 2 blue stars. After that, she cut the second ribbon into equal parts of length 50 cm and to each part she tied 5 pink stars. When she finished tying, she counted that there were 50 more pink stars than blue stars. How many stars were there altogether?

	First ribbon	Second ribbon	Difference	Total
Length of each part	40 cm	50 cm
Number of balloons tied to each part	2 blue balloons	5 pink balloons
LCM	200 cm	200 cm
Number of equal parts	200 ÷ 40 = 5	200 ÷ 50 = 4
Number of balloons for each ribbon per set	5 x 2 = 10	5 x 4 = 20	20 - 10 = 10	10 + 20 = 30

LCM of 40 and 50 = 200

Number of sets of 2 blue stars in a length of 200 cm
= 200 ÷ 40
= 5

Number of blue stars in a length of 200 cm
= 5 x 2
= 10

Number of sets of 5 pink stars in a length of 200 cm
= 200 ÷ 50
= 4

Number of pink stars in a length of 200 cm
= 4 x 5
= 20

Extra number of pink stars in a length of 200 cm
= 20 - 10
= 10

Number of sets of stars
= 50 ÷ 10
= 5

Total number of stars in one set of 200 cm of blue balloons and one set of 200 cm of pink balloons
= 10 + 20
= 30

Total number of stars of the two ribbons
= 5 x 30
= 150

Answer(s): 150