Question

1/4x + 2/5x = 39

Answer 1

Answer:

(a) $x = 60$

(b) $x = 2.64$

(c) $x=15$

Step-by-step explanation:

Solving (a):

$\frac{1}{4}x + \frac{2}{5}x = 39$

$\frac{x}{4} + \frac{2x}{5} = 39$

Take LCM

$\frac{13x}{20} = 39$

Multiply through by 20

$20 * \frac{13x}{20} = 39 * 20$

$13x = 39 * 20$

$13x = 780$

Solve for x

$x = 780/13$

$x = 60$

Solving (b):

$0.6x + 0.5x = 2.9$

This gives:

$1.1x = 2.9$

Solve for x

$x = \frac{2.9}{1.1}$

$x = \frac{29}{11}$

$x = 2.64$

Solving (c):

$\frac{3}{5}x = 9$

Multiply both sides by $\frac{5}{3}$

$\frac{5}{3}*\frac{3}{5}x = 9 * \frac{5}{3}$

$x = 9 * \frac{5}{3}$

$x = \frac{9 *5}{3}$

$x = \frac{45}{3}$

$x=15$