Question

# What will be the first proportion when third proportion is 5. Second proportion is 4 more than the first proportion and fourth proportion is 7 more than the third proportion.720720207

Solution

## The correct option is D 207Given, third proportion = 5 So, fourth proportion = 5 + 7 = 12 Let, the first proportion = a then, second proportion = a + 4 Since the ratio are in proportion, we have a : (a + 4) :: 5 : 12 Product of means = Product of extremes ∴ (a + 4) × 5 = a × 12 ⇒ 5a + 20 = 12a ⇒ 12a - 5a = 20 ⇒ 7a = 20 ⇒ a = 207 So, Proportion =  207 : (207 + 4) :: 5 : 12

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