Question

si:a/4=b/8=c/7=d/9;además :ac + bd=14 400, hallar a+b+c+d

Answer 1

Respuesta:

$\frac{a}{4} = \frac{b}{8} = \frac{c}{7} = \frac{d}{9} = k \\ a = 4k...b = 8k... \: c= 7k... \: d = 9k \\ ac + bd = 14400 \\ (4k)(7k) + (8k)(9k) = 14400 \\ 28 {k}^{2} + 72 {k}^{2} = 14400 \\ 100 {k}^{2} = 14400 \\ 10k = 120 \\ k = 12$

a + b + c + d = 4k + 8k + 7k + 9k

= 28k = 28(12) = 336