PSLE
Sarah and Rachel each had a plate of dough of the same mass for making sandwiches. The same mass of dough was used for each sandwich. Sarah made 30 sandwiches and had 450 g of dough left. Rachel made 10 sandwiches and had 1.15 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 Sarah and Rachel
= 30 - 10
= 20

1 kg = 1000 g
1.15 kg = 1.15 x 1000 = 1150 g

Difference between the remaining dough left by Rachel and Sarah
= 1150 - 450
= 700 g

Mass of 20 sandwiches = 700 g

Mass of 1 sandwich
= 700 ÷ 20
= 35 g

(b)
Total remaining dough left
= 1150 + 450
= 1600 g

Sets of 35 g
= 1600 ÷ 35
= 45 r 25

Number of sandwiches = 45

Answer(s): (a) 35 g; (b) 45