If 3A= 7B =13C, then A: B: C is equal to
2026
If 3A= 7B =13C, then A: B: C is equal to
- A.
21: 39 : 91
- B.
39 : 91 : 21
- C.
13 : 7 : 3
- D.
91 : 39 : 21
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Correct answer: D
Key idea: express A, B, C in terms of a common value.
Let 3A = 7B = 13C = k, so A = k/3, B = k/7, C = k/13.
Form the ratio A : B : C = k/3 : k/7 : k/13 = 1/3 : 1/7 : 1/13.
Clear denominators by multiplying each term by 273 (the LCM of 3, 7, 13): 273/3 : 273/7 : 273/13 = 91 : 39 : 21.
Therefore the ratio A : B : C is 91 : 39 : 21.