Question

it took Andy 3 hours to drive to a family reunion. On the way home, he was able to increase his average speed by 17mph and make the return drive in only 2 hours. Find his average speed on the return drive.

Answer 1

$\huge \bf\mathfrak \red{ANSWER:}$

$\boxed {51 mph}$

$\boxed{Step-by-step\: verification:}$

LET, THE GOING SPEED IS x AND RETURNING SPEED IS x+17.

NOW,

DISTANCE FOR GOING(D¹)

$= v \times t \\ = x \times 3 \\ = 3x$

THEN,

DISTANCE FOR RETURNING(D²)

$= v \times t \\ = (x + 17) \times 2 \\ = 2x + 34$

WE KNOW,

D¹=D²

OR,

$3x = 2x + 34$

•°•

$x = 34mph$

AGAIN,

RETURNING SPEED

$=( x+17 )mph\\ = (34 + 17 )mph\\ =51mph$

SO, THE AVERAGE SPEED ON RETURNING IS 51 mph.