SUM OF 2 NUMBERS IS 45 AND THE RATIO IS 7:8. FIND THE NUMBER.?
回答 (3)
2016-08-13 3:07 pm
✔ 最佳答案
7n+8n=45n(7+8)=45
n15=45
n=3
Numbers are
7n and 8n
7×3 and 8×3
21, 24
2016-08-13 3:19 pm
7+8 is 15
you want 45, i.e. 3 times as big, so use
21 + 24 = 45
you want 45, i.e. 3 times as big, so use
21 + 24 = 45
2016-08-13 7:30 pm
When you want to split something into a ratio, you do this:
Add the numbers in the ratio: 7 + 8 = 15
Get two fractions, using the numbers in the ratio and the total: 7/15 and 8/15.
Apply those to the total
45 x 7/15 = 21
45 x 8/15 = 24
The results should add up to the total: 21 + 24 = 45
A lot of ratio problems are done like this.
Add the numbers in the ratio: 7 + 8 = 15
Get two fractions, using the numbers in the ratio and the total: 7/15 and 8/15.
Apply those to the total
45 x 7/15 = 21
45 x 8/15 = 24
The results should add up to the total: 21 + 24 = 45
A lot of ratio problems are done like this.
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