What is 5/7 of 42?

How to calculate 5/7 of 42?

1. Multiply the whole number by the numerator of the fraction: 42 × 5 = 210
2. Divide this result by denominator of the fraction: 210/7 = 30
3. Simplify by dividing both the numerator and denominator by their GCD (7):
   • 210/7 = 30
   • 7/7 = 1
4. Which gives: 30/1

How does it work?

The principle behind finding a fraction of a number, such as 5/7 of 42, is rooted in the method of cross-multiplication.

Consider the following proportion: $\frac{5}{7}=\frac{x}{42}$ (where x represents 5/7 of 42)

1. Using the cross-multiplication method, multiply both numerators by their opposite denominators: $5\times 42=7x$
2. Which gives: $210=7x$
3. Divide both sides by 7 to isolate x: $\frac{210}{7}=\frac{7x}{7}$
4. Which gives the result: $\frac{210}{7}=x$ (or $\frac{30}{1}=x$)

Thus, 5/7 of 42 is equal to 30/1 (or 30 in its decimal form).