PSLE
Esther and Joelle each had a plate of dough of the same mass for making sandwiches. The same mass of dough was used for each sandwich. Esther made 31 sandwiches and had 410 g of dough left. Joelle made 15 sandwiches and had 1.05 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 Esther and Joelle
= 31 - 15
= 16

1 kg = 1000 g
1.05 kg = 1.05 x 1000 = 1050 g

Difference between the remaining dough left by Joelle and Esther
= 1050 - 410
= 640 g

Mass of 16 sandwiches = 640 g

Mass of 1 sandwich
= 640 ÷ 16
= 40 g

(b)
Total remaining dough left
= 1050 + 410
= 1460 g

Sets of 40 g
= 1460 ÷ 40
= 36 r 20

Number of sandwiches = 36

Answer(s): (a) 40 g; (b) 36