Tim bought 12 more erasers than Mark and Mark bought 24 erasers more than Tommy. The total number of erasers Tim and Mark bought was 5 times the number of erasers Tommy bought.
- How many erasers does Tim need to give Mark so that they have the same number of erasers?
- How many erasers did all three of them have altogether?
(a)
Since Tim had 12 erasers more than Mark, Tim needed to give half of his extra erasers to Mark.
Number of erasers that Tim needs to give to Mark
= 12 ÷ 2
= 6
(b)
Number of erasers that Tommy bought = 1 u
Number of erasers that Mark bought = 1 u + 24
Number of erasers that Tim bought
= 1 u + 24 + 12
= 1 u + 36
Number of erasers that Mark and Tim bought
= 1 u + 24 + 1 u + 36
= 2 u + 60
Total number of erasers that Tim and Mark bought is 5 times the number that Tommy bought.
Number of erasers that Mark and Tim bought = 5 u
5 u = 2 u + 60
5 u - 2 u = 60
3 u = 60
1 u = 60 ÷ 3 = 20
Total number of erasers
= 5 u + 1 u
= 6 u
= 6 x 20
= 120
Answer(s): (a) 6; (b) 120
