PSLE
Betty and Yoko each had a plate of dough of the same mass for making sandwiches. The same mass of dough was used for each sandwich. Betty made 34 sandwiches and had 470 g of dough left. Yoko made 16 sandwiches and had 1.28 kg of dough left.

1. What was the mass of dough needed for each sandwich?
2. With the remaining dough from both girls, how many more such sandwiches can be made at most? 

(a)
Difference between the number of sandwiches made by Betty and Yoko
= 34 - 16
= 18

1 kg = 1000 g
1.28 kg = 1.28 x 1000 = 1280 g

Difference between the remaining dough left by Yoko and Betty
= 1280 - 470
= 810 g

Mass of 18 sandwiches = 810 g

Mass of 1 sandwich
= 810 ÷ 18
= 45 g

(b)
Total remaining dough left
= 1280 + 470
= 1750 g

Sets of 45 g
= 1750 ÷ 45
= 38 r 40

Number of sandwiches = 38

Answer(s): (a) 45 g; (b) 38