PSLE
Yen had two strings of the same length. She cut the first string into equal parts of length 60 cm and to each part she tied 2 pink balloons. After that, she cut the second string into equal parts of length 100 cm and to each part she tied 4 red balloons. When she finished tying, she counted that there were 10 more red balloons than pink balloons. How many balloons were there altogether?

	First string	Second string	Difference	Total
Length of each part	60 cm	100 cm
Number of balloons tied to each part	2 pink balloons	4 red balloons
LCM	300 cm	300 cm
Number of equal parts	300 ÷ 60 = 5	300 ÷ 100 = 3
Number of balloons for each string per set	5 x 2 = 10	4 x 3 = 12	12 - 10 = 2	10 + 12 = 22

LCM of 60 and 100 = 300

Number of sets of 2 pink balloons in a length of 300 cm
= 300 ÷ 60
= 5

Number of pink balloons in a length of 300 cm
= 5 x 2
= 10

Number of sets of 4 red balloons in a length of 300 cm
= 300 ÷ 100
= 3

Number of red balloons in a length of 300 cm
= 3 x 4
= 12

Extra number of red balloons in a length of 300 cm
= 12 - 10
= 2

Number of sets of balloons
= 10 ÷ 2
= 5

Total number of balloons in one set of 300 cm of pink balloons and one set of 300 cm of red balloons
= 10 + 12
= 22

Total number of balloons of the two strings
= 5 x 22
= 110

Answer(s): 110