"Today Grandma rode 20% further than she rode on Sunday, in 20% less time than Sunday's ride took. Her speed today was _% of her speed on Sunday."
A) 140
B) 150
C) 160
D) 170
Can you please explain your answer if you know the answer, because I am very confused. Thanks to all who reply!
2007-02-01 08:35:28 · 14 answers · asked by Anonymous in Education & Reference ➔ Homework Help
This is the complete question, and I am guessing you can see why I am confused. I am trying to figure out how to do this for future refrence, so a guess won't really help. Thanks.
2007-02-01 08:41:27 · update #1
the answer is B.
lets say that on sunday she rode 100 miles in 100 min.
then Today she road 100miles + 20miles=120 miles
she did it 20% faster meaning she made it in 80 min
divide 120 by 80 and multiply by 100= 150%
2007-02-01 08:42:30 · answer #1 · answered by Shmesh 3 · 1⤊ 0⤋
speed = distance / time
This is the formula for speed.
1) To calculate this make the distance and time of Sunday equal 100.
sunday speed = 100 / 100 = 1 --> 100%
2) For today the since the distance was 20% more, increase 20 to the normal distance, and the time since it is 20% less, subtract 20 of the normal time. Calculate the result.
today speed = (100+20) / (100-20) = 120 / 80 = 3/2 = 1.5 --> 150%
3) The result was 1.0 for Sunday which would be equivalent to 100% speed. For today it is 1.5, which means the speed is now 150%.
2007-02-01 08:44:10 · answer #2 · answered by JC 301186 3 · 0⤊ 0⤋
well the answer is B 150. the formula for speed is distance divided by time equals speed. so if grandma rode 10 miles on sunday in 10 minutes (i just used 10 because its easy i doubt anyones grandma could ride 10 miles in 10 minutes) then 20% percent of 10 is 2 which in distance you add to ten in distance and subtract in time. So today granma rode 12 miles in 8 minutes. so you divide todays distance by todays speed and get 1.5 miles per hour. Then you divide sundays distance by sundays time and get 1 mile per minute. Well if it was the same speed as sundays it would be 100% of her speed on sunday but it was faster by .5 so its 150% of her speed on sunday. And just realized how confusing that was so heres the math.
10 miles on sunday 10 x 20% = 2 10 + 2 = 12 miles today
10 minutes on sunday 10 x 20% = 2 10 - 2 = 8 minutes today
10 / 10 = 1 minute per hour on sunday
12 / 8 = 1.5 minutes per hour today
1 = 100% 1 times 100 thats how you get percents
1.5= 150% 1.5 times 100
hope that helped sorry if it was confusing
2007-02-01 08:56:57 · answer #3 · answered by moonestone182 2 · 0⤊ 0⤋
Grandma rode 20% further... so she rode 120% of her previous ride.
or
x = distance of previous ride
1.2x = distance of this ride
Her time was 20% less... so her time was 80% of her previous time.
or
y = previous time
.8y = this time
Since speed is equal to distance divided by time...
S = previous speed and s = this speed
S = x/y and s = 1.2x / .8y
s = 1.5(x/y)
s = 1.5 S or this speed is 150% of the previous
Others have the correct answer, and one even showed an example... but I've explained the math. If you're still confused, remember these formulas:
Distance = Rate (speed) X Time
Rate (speed) = Distance / Time
Time = Distance / Rate (speed)
and remember that % must always be converted into a decimal before you can perform math.
2007-02-01 11:42:42 · answer #4 · answered by sagacity_ron 2 · 0⤊ 0⤋
distance milestime taken hrs
2020100
2416150
lets suppose she travelled 20 miles in 20 hrs on sunday.
She travelled 20% more today which is which is 24 miles
in 20% less time i.e. 16 hrs
the equation for this is distance travelled divided by time taken multiplied by 100 (to take the percentage out)
see the above eg. hope it helpped or ask again?
so the ans. is 150
2007-02-01 08:54:39 · answer #5 · answered by istupidice 2 · 0⤊ 0⤋
The answer is B) 150.
Let's say she traveled 5 miles on Sunday and it took her 5 minutes to travel those 5 miles. Her rate was 1 mph (The one is important here).
Then today she traveled 6 miles (20% more than 5 miles) and it took her 4 minutes (20% less than 5 minutes) to travel those 6 miles. Her rate is 1.5 mph. 1.5 is 150% of 1.
2007-02-01 08:42:32 · answer #6 · answered by Scottee25 4 · 1⤊ 0⤋
Take it like this. If she did 60 miles in 1 hr on Sunday then she will do 72 miles in 48 minutes. You get 72/48 and you have 150%
2007-02-01 08:40:34 · answer #7 · answered by andyramvzb 3 · 2⤊ 0⤋
150
2007-02-01 08:43:24 · answer #8 · answered by bog_blasted 1 · 0⤊ 0⤋
There are several good answers, so I don't need to add mine. But in my opinion, the answer from sagacity was the clearest for somebody who is struggling with the concept.
2007-02-01 12:14:38 · answer #9 · answered by Irma R 2 · 0⤊ 0⤋
Answer: 150
Speed = D/T (Distance / Time)
Sunday = D1/T1
Today = (D1*120%)/(T1*80%) - Distance increased, time decreased
Calculation:
((D1*120%)/T1) / (T1*80%)/T1 - Distributive Property
((D1*120%)/T1) / 80% - Simplify
((D1*120%)/(T1*120%) / (80%/120%) - Distributive Property
D1/T1 / 80%/120%
D1/T1 * 120%/80%
D1/T1 * 150%
2007-02-01 08:58:04 · answer #10 · answered by brucease 1 · 0⤊ 0⤋