Brad walks and jogs to schooll every day. He averages 5 km/hr walking and 9 km/hr jogging. The distane from home to shool is 6 km, and the total trip takes 1 hour. How far does Brad walk?

Question

anonymous · Answer

6-x/9 + x/5 = 1 
9x +30 - 5x = 45 
4x = 15 
x = 3.75 km 
He walks 3.75 km

anonymous · Answer

Let x be the time taken he walk to school every day and y be the time taken he run to school every day. Use x and y to form 2 distinct equations to solve for the answer.

Given that total trip takes 1 hour, 
x+y = 1 - (1)

Give the speed of 5km/hr for walking and 9km/hr for jogging,
5x+9y = 6 -(2)

Taking eqn.(1) and multiply by 5.

x+y= 1
5x+5y = 5 - (3)

take eqn.2 and subtract eqn.3

5x+9y - (5x +5y) = 6-5
4y = 1
y= 1/4

Since y=1/4 , from eqn.1
x+ (1/4) = 1
x = 3/4

He walks for 3/4 hr = 45mins.