SOLUTION: Hi, Every day Rachel walks 20 km at a certain speed. One day Rachel left 30 minutes late so she increased her speed by 25 kmh and as a result reached her destination 20 minutes ea

Question 1035107: Hi,
Every day Rachel walks 20 km at a certain speed. One day Rachel left 30 minutes late so she increased her speed by 25 kmh and as a result reached her destination 20 minutes early. How long does she generally take to walk?
Thanks!
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39615) (Show Source): You can put this solution on YOUR website!
Twenty minutes is .

RATE TIME DISTANCE NORMAL r t 20 ONEDAY r+25 20

Tricky part may be examining an expression for travel time on ONE DAY.
She left half hour later and arrival was one-third of hour early.

Simplify the ONE DAY equation first.
Multiply left and right by 6.

Use the NORMAL DAY equation to substitute for rt.

divide sides by 5.

Now you have a simpler system of equations:

and this should give you a quadratic equation to solve for either variable; and use it to find the other variable.
Answer by MathTherapy(10549) (Show Source): You can put this solution on YOUR website!

Hi,
Every day Rachel walks 20 km at a certain speed. One day Rachel left 30 minutes late so she increased her speed by 25 kmh and as a result reached her destination 20 minutes early. How long does she generally take to walk?
Thanks!

With T being normal walk-time, time taken on that day: , leading to the following SPEED equation: .
Solving for T gives a normal walk-time of:
RELATED QUESTIONS
Rachel is driving to an appointment. at her current speed she will be 11 minutes late and (answered by ewatrrr)
Charlotte walks to work every morning. It takes 40 minutes if she walks at 4.5 km/h. How... (answered by ewatrrr)
Jennifer and her her brother Michael enjoy racing each other. One day, Michael... (answered by josgarithmetic)
when a bicyclist is 20 km from her destination she realizes that she will be 10 minutes... (answered by ikleyn)
Angnette rides her bike every day. If she rides at a constant speed of 10 mph every time... (answered by richwmiller)
A girl walks 24 km at the speed of x km/hr and 40 km at the speed of y km/hr on 1st day.... (answered by josgarithmetic)
Jodi walks to school every morning. If she walks at a speed of 50 meters per minute, she... (answered by mananth)
Susie runs a mile every day for a week (7DAYS). Her average speed is 8 minutes. She... (answered by ankor@dixie-net.com)
Rachel left the science museum one hour before Jacob. They traveled in opposite... (answered by ewatrrr,advanced_Learner)