Solve 21/4:13/8=

$$2 \frac { 1 } { 4 } : 1 \frac { 3 } { 8 } =$$

Evaluate

$$\frac{18}{11}\approx 1.636363636$$

Solution Steps

Divide \frac{2\times 4+1}{4} by \frac{1\times 8+3}{8} by multiplying \frac{2\times 4+1}{4} by the reciprocal of \frac{1\times 8+3}{8}.

$$\frac{\left(2\times 4+1\right)\times 8}{4\left(1\times 8+3\right)}$$

Cancel out 4 in both numerator and denominator.

$$\frac{2\left(1+2\times 4\right)}{3+8}$$

Multiply 2 and 4 to get 8.

$$\frac{2\left(1+8\right)}{3+8}$$

Add 1 and 8 to get 9.

$$\frac{2\times 9}{3+8}$$

Multiply 2 and 9 to get 18.

$$\frac{18}{3+8}$$

Add 3 and 8 to get 11.

$$\frac{18}{11}$$

Factor

$$\frac{2 \cdot 3 ^ {2}}{11} = 1\frac{7}{11} = 1.6363636363636365$$