Question

Cassius drives his boat upstream for 45 minutes. It takes him 30 minutes to return downstream. His speed going upstream is 3 miles per hour slower than his speed going downstream. Find his upstream and downstream speed

Answer 1

Answer:

Upstream speed= 6 mile per hour

Downstream speed= 9 miles per hour

Step-by-step explanation:

Distance traveled during upstream

= x miles

Distance traveled during downstream

= y

Time traveling upstream

= 45 minutes.

Time traveling downstream

= 30 minutes

Speed traveling upstream

= a miles/hour

Speed traveling downstream

= b miles/hour

But

b = a+3

Distance= speed*time

X=45a

a= x/45

Y= 30(a+3)

Y= 30a +90

a= (y-90)/30

Equating both a

X/45= (y-90)/30

30x= 45(y-90)

X= 1.5y-135

But x= y

Y= 1.5y-135

135= 0.5y

270 miles = y

Y= x= 270 miles

X= 45a

270/45= a

6 mile/hour = a

b = a+3

b= 6+3

b = 9 miles/hour