Question

已知：a/b = c/d = e/f = 1/4，3b+d+7f=16, 求3a+c+7e=？

Answer 1

a/b = c/d = e/f = 1/4
a=b/4
c=d/4
e=f/4
3a+c+7e=1/4*(3b+d+7f)=4

Answer 2

a/b = c/d = e/f = 1/4，
b=4a,d=4c,f=4e
所以
3b+d+7f=16,
=12a+4c+28e=4(3a+c+7e)
所以
3a+c+7e=16/4=4

Answer 3

a/b = c/d = e/f = 1/4，则b=4a，d=4c，f=4e
3b+d+7f=16，则12a+4c+28e=16
则4(3a+c+7e)=16
所以3a+c+7e=4

Answer 4

(3a+c+7e)/(3b+d+7f)=a/b=1/4
3a+c+7e=1/4*(3b+d+7f)
=1/4*16
=4