PSLE
Barbara and Kimberly each had a plate of dough of the same mass for making sandwiches. The same mass of dough was used for each sandwich. Barbara made 38 sandwiches and had 190 g of dough left. Kimberly made 18 sandwiches and had 1.09 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 Barbara and Kimberly
= 38 - 18
= 20

1 kg = 1000 g
1.09 kg = 1.09 x 1000 = 1090 g

Difference between the remaining dough left by Kimberly and Barbara
= 1090 - 190
= 900 g

Mass of 20 sandwiches = 900 g

Mass of 1 sandwich
= 900 ÷ 20
= 45 g

(b)
Total remaining dough left
= 1090 + 190
= 1280 g

Sets of 45 g
= 1280 ÷ 45
= 28 r 20

Number of sandwiches = 28

Answer(s): (a) 45 g; (b) 28