Ai Tong School P5 Math CA1 2006 (Q46)

Joyce is paid $1.10 for every calculator she sells. She receives a bonus of $20 for every 150 calculators she sells. How many calculators must she sell to earn $1002?

Solution

1 calculator ----- $1.10
1 group of 150 calculators ----- (150 x $1.10) + bonus
= $165 + $20
= $185

5 groups of 150 ----- $185 x 5 = $925
6 groups of 150 ----- $185 x 6 = $1110

Therefore, to earn $1002, she has to sell 5 groups of 150 calculators plus….

$1002 - $925 (her pay for 5 groups of 150)
= $77

1 calculator ----- $1.10
$77 divided by $1.10 ----- 70 individual calculators

Total number of calculators that she has to sell

5 groups of 150 + 70
= (5 x 150) + 70
= 750 + 70
= 820

Answer: She has to sell 820 calculators to earn $1002.