Level 2
Gopal went to a shop with 3 fifty-dollar notes. He bought a watch and a calculator. A watch cost 3 times as much as a calculator. He received $32.40 change. How much did the calculator cost?

Level 3
At a book shop, Alice paid $12 for 1 book and 2 pens. The book cost $6 more than the total cost of all the pens.

1. How much did 1 pen cost?
2. How much did 1 book cost?

Level 3
At a book shop, Alice paid $12 for 1 book and 2 pens. The book costs $6 less than the total cost of all the pens.

1. How much did 1 book cost?
2. How much did 1 pen cost?

Level 3
Oscar Mobile Company has a few mobile phone service plans. Plan A offers 270 SMS and 90 minutes of talk time for $25.20. Plan B offers 370 SMS and 190 minutes of talk time for $35.20. Oscar Mobile Company is also going to launch Plan C which offers 170 SMS and 260 minutes of talk time. How much should Oscar Mobile Company charge for Plan C if the cost per SMS and the cost per minute of talk time do not vary across the three plans?

Level 3
Mrs Decruz baked 8 muffins more than cakes. Each muffin needed 0.06 kg of flour while each cake needed 0.5 kg of flour. She used 1.72 kg more flour for the cakes than for the muffins. How many muffins did Mrs Decruz bake?