PSLE Sabrina started a savings plan by putting 2 coins into a money box every day. Each coin was either a 20¢ or 50¢ coin. Her mother also put in $5 note in the box every 3 days. The total value of the savings after 114 days was $276.40.
- How many coins were there altogether?
- How many of the coins were 50¢ coins?
(a)
Total number of coins
= 2 x 114
= 228
(b)
Number of sets of 3 days
= 114 ÷ 3
= 38
Amount that her mother put in
= 38 x 5
= $190
Amount that Sabrina saved by herself
= 276.40 - 190
= $86.40
Number of 50¢ |
Value of 50¢ |
Number of 20¢ |
Value of 20¢ |
Total value |
228 |
228 x 0.5 = 114 |
0 |
0 |
114 |
227 |
227 x 0.5 = 113.5 |
1 |
1 x 0.2 = 0.2 |
113.7 |
Small difference
= 114 - 113.7
= 0.3
Big difference
= 114 - 86.4
= 27.6
$1 = 100¢
$0.30 = 0.30 x 100 = 30¢
$27.60 = 27.60 x 100 = 2760¢
Number of 20¢ coins
= 2760 ÷ 30
= 92
Number of 50¢ coins
= 228 - 92
= 136
Answer(s): (a) 228; (b) 136