There were some children in a museum.
13 of the children lined up in 8 short rows and
15 of the children lined up in 4 long rows. The remaining children did not line up. There are 7 more children in each long row than each short row.
(a) What fraction of the children did not line up?
(b) How many children lined up?
|
Short rows |
Long rows |
Number |
8 |
4 |
Value |
1 u |
1 u + 7 |
Total value |
8 u |
4 u + 28 |
(a)
Fraction of children who did not line up
= 1 -
13 -
15 = 1 -
515 -
315= 1 -
815=
715(b)
515 of the children lined up in short rows.
8 u = 5 p --- (1)
315 of the children lined up in long rows.
4 u + 28 = 3 p --- (2)
(1)
x3
24 u = 15 p --- (3)
(2)
x5
20 u + 140 = 15 p --- (4)
(3) = (4)
24 u = 20 u + 140
24 u - 20 u = 140
4 u = 140
1 u = 140 ÷ 4 = 35
Number of children who lined up
= 8 u + 4 u + 28
= 12 u + 28
= 420 + 28
= 448
Answer(s): (a)
715; (b) 448