If a varies directly as the cube root of b and if a=3 and b=64.find the formula connecting the variables hence find b when a=15/4

b = 125

Step-by-step explanation:

Given a varies directly as then the equation relating them is

a = k ← k is the constant of variation

To find k use the condition a = 3 , b = 64 , then

3 = k = 4k ( divide both sides by 4 )

= k

a = ← equation of variation

When a = , then

= ( multiply both sides by 4 to clear the fractions )

15 = 3 ( divide both sides by 3 )

5 = , then

b = 5³ = 125

each side has a different length.  

step-by-step explanation:

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.