PSLE
Tiffany and Opal made some apple sandwiches and banana sandwiches. Tiffany made 29 more apple sandwiches than banana sandwiches. Opal made 143 more banana sandwiches than apple sandwiches. The total number of apple sandwiches made up 31% of the total number of sandwiches they made. How many apple sandwiches did they make altogether?

Number of banana sandwiches		Number of apple sandwiches
69%		31%
Tiffany	Opal	Tiffany	Opal
1 u	1 p + 143	1 u + 29	1 p

Tiffany
Number of banana sandwiches = 1 u
Number of apple sandwiches = 1 u + 29

Opal
Number of apple sandwiches = 1 p
Number of banana sandwiches = 1 p + 143

Number of banana sandwiches in percent
= 100% - 31%
= 69%

1 u + 29 + 1 p = 31% --- (1)
1 u + 1 p + 143 = 69% --- (2)

(2) - (1)
69% - 31% = 143 - 29
38% = 114

1% = 114 ÷ 38 = 3

Number of apple sandwiches that they made altogether
= 31%
= 31 x 3
= 93

Answer(s): 93