There are 20% as many black marbles as red marbles in Vanessa's collection of marbles. The number of silver marbles is 30% fewer than the number of red marbles. There are 530 more silver marbles than black marbles.
- Find the total number of marbles in the collection.
- What percentage are the number of red marbles as compared to the number of silver marbles? Leave your answer as a mixed number in its simplest form.
Black |
Red |
Silver |
1x2 |
5x2 |
|
|
10x1 |
7x1 |
2 u |
10 u |
7 u |
(a)
20% =
20100 =
15 100% - 30% = 70%
70% =
70100 =
710 The number of red marbles is the repeated identity. Make the number of red marbles the same. LCM of 5 and 10 is 10.
Number of more silver marbles than black marbles
= 7 u - 2 u
= 5 u
5 u = 530
1 u = 530 ÷ 5 = 106
Total number of marbles in the collection
= 2 u + 10 u + 7 u
= 19 u
= 19 x 106
= 2014
(b)
Percentage of the number of red marbles as compared to the number of silver marbles
=
107 x 100%
=
10007 %
= 142
67 %
Answer(s): (a) 2014; (b) 142
67 %