06 Apr, 2010
Hamsters
Ref : P3 Lesson 12
These are only 3 cages and some hamsters at Cutie Pet Shop as shown below. At Cutie Pet Shop, there is a rule that there can only be a maximum of 5 hamsters in a cage. The owner of the pet house had ordered another 35 hamsters and they will arrive next week. What is the least number of cages the owner needs to buy to keep all the hamsters in Cutie Pet house?
>>Solution
In Pet house : 6 hamsters (as shown in picture)
Additional: 35 hamsters
Total hamsters : 6 + 35 = 41 hamsters
1 cage = max 5 hamsters
41 ÷ 5 = 8 R1
Here ‘8’ means there will be 8 cages with 5 hamsters in each cage
Remainder ‘1’ means there will be one hamster ‘left’
We can’t leave this hamster running around the pet house, can we? We need to put this ONE hamster into ONE cage.
Total: we need 8 + 1 = 9 cages to keep all 41 hamsters.
There are already 3 cages in the pet shop.
So the owner needs to buy 9 - 3 = 6 cages more
Answer : 6 cages
06 Apr, 2010
Cough Mixture
Ref : P3 Lesson 12
Simone went to the doctor on Tuesday night. She was told by her doctor to take 1 dose of cough syrup 3 times a day. She started to her first does of medication on Tuesday night. She went back to the doctor when her cough syrup ran out. Which day of the week did she go back to visit the doctor again?
>>Solution
Heuristic : Make a systematic list
Monday (night) : 5ml
Subsequent Days : 1 dose x 3 times x 5ml = 15ml
90ml - 5ml (taken on Monday night) = 85 ml
85 ÷ 15 = 5 remainder 10
Here, ‘5’ means 5 more days : Tuesday - Saturday
Remainder ‘10’ means 10ml left after Saturday
10ml = 5ml (Sunday Morning) + 5ml (Sunday afternoon)
Answer : Simone will finish her medicine by Sunday afternoon.
She will go back to her doctor on SUNDAY.
