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If 2a=6b and 9b=7c, Find a:b:c?
- A42:18:14
- B3:9:7
- C9:27:22
- D21:7:9
Correct answer: D
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CCommunity
21:7:9
NA
NA
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Solution:
Given:
2a = 6b and 9b = 7c
b = 2a/6
b = a/3
Substituting this in the second equation we get,
9(a/3) = 7c
3a = 7c
c = 3a/7
Now, a : b : c = a : a/3 : 3a/7
= 1 : 1/3 : 3/7
× 3
= 3 : 1 : 9/7
×7
= 21 : 7 : 9
So, the correct option is D). 21 : 7 : 9
Given:
2a = 6b and 9b = 7c
b = 2a/6
b = a/3
Substituting this in the second equation we get,
9(a/3) = 7c
3a = 7c
c = 3a/7
Now, a : b : c = a : a/3 : 3a/7
= 1 : 1/3 : 3/7
× 3
= 3 : 1 : 9/7
×7
= 21 : 7 : 9
So, the correct option is D). 21 : 7 : 9