Maths Help
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Maths Help
Please can someone explain how to solve the questions below?
Frank takes 2 hours minutes to do a journey at an average speed of 40 mph. How far does he go.
Janet does the same journey in 2 hours. What is her average speed?
Cheers
Frank takes 2 hours minutes to do a journey at an average speed of 40 mph. How far does he go.
Janet does the same journey in 2 hours. What is her average speed?
Cheers
Hi, ladyy, you have forgotten to give the number of minutes that Frank takes. I'll say 30 minutes.
If frank goes at 40mph, he goes at 40/60 miles (=2/3 mile) per minute.
So in 1 minute, he does 2/3 mile.
In 2 hours 30 minutes (=150 mnns) he does 2/3 mile * 150 = 300/3 = 100miles
Janet does 100 miles in 2 hours , so 50 miles in 1 hr. Her speed is 50mph.
Hope this helps
Catherine
If frank goes at 40mph, he goes at 40/60 miles (=2/3 mile) per minute.
So in 1 minute, he does 2/3 mile.
In 2 hours 30 minutes (=150 mnns) he does 2/3 mile * 150 = 300/3 = 100miles
Janet does 100 miles in 2 hours , so 50 miles in 1 hr. Her speed is 50mph.
Hope this helps
Catherine
Maths Help
I typed the question wrongly, it should be
Frank takes 2 hours 30 minutes to do a journey at an average speed of 40 mph. How far does he go.
Janet does the same journey in 2 hours. What is her average speed?
I now know how to explain it to my son.
Thanks a once again.
Frank takes 2 hours 30 minutes to do a journey at an average speed of 40 mph. How far does he go.
Janet does the same journey in 2 hours. What is her average speed?
I now know how to explain it to my son.
Thanks a once again.
I think the important point here is to make they learn the 3 different SDT equations, and also remember to convert time into the correct units.
In my children's junior school (a few years ago now) they did study skills lesson and used a SDT pyramid method to help the children remember (and work out) the 3 equations: S=D/T etc.
In theory it's not essential for 11+ but my children found this invaluable. If they are doing any Independent 11+ exams as well then this is certainly essential.
In my children's junior school (a few years ago now) they did study skills lesson and used a SDT pyramid method to help the children remember (and work out) the 3 equations: S=D/T etc.
In theory it's not essential for 11+ but my children found this invaluable. If they are doing any Independent 11+ exams as well then this is certainly essential.
I'm not totally sure of the method myself, but it was something my daughter was taught in school to remember the 3 equestions:-
Speed = Distance/Time
Speed x Time = Distance
Time = Distance/Speed
I seem to recall they got the children to write SDT in a pyramid with D at the top, S on the left and T on the Right. They then drew perpendicular lines from the centre of each side to a point in the middle of pyramid.
No sure why this did this, I've always remembers S=D/T and then just simply rearranged!
Ken
Speed = Distance/Time
Speed x Time = Distance
Time = Distance/Speed
I seem to recall they got the children to write SDT in a pyramid with D at the top, S on the left and T on the Right. They then drew perpendicular lines from the centre of each side to a point in the middle of pyramid.
No sure why this did this, I've always remembers S=D/T and then just simply rearranged!
Ken
Kenr, as you say you have D on top, line and S X T on bottom. The idea is that you cover the one you want and this gives you how to calculate it. Thus, if you cover the D, you are left with S x T. If you cover the S, you see D/T (i.e. D divided by T) etc.
Unfortunately the children who don't get the whole concept of speed, time and distance tend to be the same children who can't remember which number is where in the triangle.
They do these same triangles further up the school in the sciences as an aide to memory.
Unfortunately the children who don't get the whole concept of speed, time and distance tend to be the same children who can't remember which number is where in the triangle.
They do these same triangles further up the school in the sciences as an aide to memory.