https://www.kiasuparents.com/kiasu/question/79669-2/
If you want to let your kid practice Guess-and-Check, can try below. Total Qty is 120. As kids progress with more complex methods, they may drop the “troublesome” Guess-and-Check method but it is still a good thing to practice once in a while until the big PSLE. Can also consider a little hybrid by making supposition (for every exchange) to save some time on guess and check. Still three sets of checking in below table.
$ per T-shirt |
Qty of T-shirts |
Total $ T-shirts |
$ per shorts |
Qty of shorts |
Total $ Shorts |
Diff |
$12.50 |
let’s take 60 |
$750 |
$11 |
60 |
$660 |
$90 |
|
suppose 61 |
$762.50 |
|
59 |
$649 |
$113.50 |
|
*see note |
|
|
*see note |
|
*see note |
|
69 |
$862.50 |
|
51 |
$561 |
$301.50 ok |
*analyse and deduce that for every one set of exchange from 1 pair of shorts to 1 T-shirt, Benny is spending $113.50-$90 = $23.50 more on T-shirts. (Or save $11 + spend $12.50 = $23.50 more on T-shirts)
$301.50 – $113.50 = $188.00
$188.00 / $23.50 = 8 more exchanges (–> 59-8 = 51 pairs of shorts) (–> 61+8 = 69 T-shirts).
Put back into table and check*
(a) 51 pairs of shorts#
(b) $862.50 + $561= $1423.50#