Find the value of k if 5 : k :: 30 : 42.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 7
When two ratios are in proportion, the product of the means equals the product of the extremes. We can use this property to solve for the unknown value of k.
The given ratio is 5 : k :: 30 : 42. We can write this as:
5 : k = 30 : 42
Using the cross-multiplication property, we get:
5 × 42 = k × 30
210 = 30k
k = 7