Crosswords5 mins ago
Maths Problem!
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Been absolute yonks since I've done any maths and was given this recently but am completely stuck!! Embarrassed to say, that this is a primary school question!!
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For more on marking an answer as the "Best Answer", please visit our FAQ.Don't be embarrassed at not solving that problem: if you're out of practice then it's probably not at all obvious what to do. Right now I'm way too tired to think properly, too.
Maybe a trial-and-error approach is the most intuitive way to solve it. If Jonas cycled for two hours and walked the rest of the time then he'd have travelled (12 x 2) + 4 = 28 miles, so that's just a little too long. If he cycled one hour and walked two hours then he'd have done 12 + (4 x 2) = 20 miles instead.
Next you can try one-and-a-half hours, for a total journey length of (12 x 1.5) + (4x1.5) = 18 + 6 = 24 miles. Still too short, so go half-way again: 12 x (one and 3/4) + 4 x (1 and 1/4) = 21 + 5 = 26.
That works! There are clearly more mathematical solutions, but guesswork can anyway help you get into the problem and is maybe easier to have a handle on.
So anyway Jonas was walking for one-and-a-quarter hours and cycled 21 miles.
Maybe a trial-and-error approach is the most intuitive way to solve it. If Jonas cycled for two hours and walked the rest of the time then he'd have travelled (12 x 2) + 4 = 28 miles, so that's just a little too long. If he cycled one hour and walked two hours then he'd have done 12 + (4 x 2) = 20 miles instead.
Next you can try one-and-a-half hours, for a total journey length of (12 x 1.5) + (4x1.5) = 18 + 6 = 24 miles. Still too short, so go half-way again: 12 x (one and 3/4) + 4 x (1 and 1/4) = 21 + 5 = 26.
That works! There are clearly more mathematical solutions, but guesswork can anyway help you get into the problem and is maybe easier to have a handle on.
So anyway Jonas was walking for one-and-a-quarter hours and cycled 21 miles.
I would also do it by trial and error, but If you want to do it by solving simultaneous equations, then
Let x = the distance walked and Let y = the distance cycled
Obviously x + y = 26
Second equation x/4 + y/12 = 3 hours
Get rid of the fractions by multiplying everything by 12
Equation 2 becomes
3x + y = 36
Therefore solve
3x + y = 36
x + y = 26
Subtract bottom from top
2x = 10
x = 5
As x + y = 26 and x = 5, it follows that y = 21
This gives the answer which you already know is correct
Let x = the distance walked and Let y = the distance cycled
Obviously x + y = 26
Second equation x/4 + y/12 = 3 hours
Get rid of the fractions by multiplying everything by 12
Equation 2 becomes
3x + y = 36
Therefore solve
3x + y = 36
x + y = 26
Subtract bottom from top
2x = 10
x = 5
As x + y = 26 and x = 5, it follows that y = 21
This gives the answer which you already know is correct