Akira and Hideo are twins with different jobs. Akira earns five-eighths of what Hideo earns, but Akira’s expenses are half of Hideo’s. Akira ends up saving 40% of his income. What percentage of his income does Hideo save?

x=30

step-by-step explanation:

graph #4 (last graph) depict the function   f(x)= -m(x-d)^1/5 i

step-by-step explanation:

we know that

m=slope

but in this function slope is -m that means slope is decreasing and it is decreasing by 1/5 points down the x-axis.

which is shown in graph four

a decreasing slope down x-axis by 1/5 points.

hence 4th graph is the right option for this.