What must be added to each term of the ratio 7 : 11 to make it equal…

The correct answer is Option (3) → 5

Let the number added to each term be \(x\). The new ratio \((7+x):(11+x)\) must equal \(3:4\), and two equal ratios give equal cross products.

• The new ratio equal to 3 : 4: \(\displaystyle\frac{7+x}{11+x}=\frac{3}{4}\)

• Equal cross products: \(4(7+x)=3(11+x)\)

• \(28+4x=33+3x\)

• So the number to be added is \(x=5\)