PSLE Tammy has a number of pens in three colours: red, green and brown.
57 of the pens are red. The number of red pens is thrice the number of green pens. What fraction of the pens is brown?
Red |
Green |
Brown |
Total |
5x3 |
2x3 |
7x3 |
3x5 |
1x5 |
|
|
15 u |
5 u |
1 u |
21 u |
Number of red pens is the repeated identity.
Make the number of red pens the same.
LCM of 5 and 3 = 15
Number of brown pens
= 21 u - 15 u - 5 u
= 1 u
Fraction of the pens that is brown
=
121 Answer(s):
121