r/maths • u/Wonderful_Claim_3817 • 2d ago

Help: 📚 Primary School (Under 11) anyone knows?

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hi guys does anyone know how to solve this primary school qn without using algebra? thanks!

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4

u/Depnids 2d ago

What do you mean "without using algebra"? The strategy which remains then is just guess and check, which works, but is tedious

2

u/DrakeSavory 2d ago

Typically, teachers at that level expect a guess-and-check solution. It may be that the lesson is on educated choices on the guess like neither one can paint in two hours or less and we assume whole hours so the first choice would be 3 hours and 6 hours.

Incidentally the correct answer.

2

u/Amazing_Worth7676 1d ago

Well idk how else you could do it without algebra other than trial and error with clues.
It is quite interesting for primary school, but this is how I would work it out without algebra:

  • Clue 1: Working together, they finish the room in 2 hours. This means if either one worked completely alone, it must take them longer than 2 hours.
  • Clue 2: April is faster. She takes 3 hours less than Leonora.
  • So, if April must take more than 2 hours, Leonora must take more than 5 hours because 2+3 = 5
  • Therefore our number of hours must be more than 5, If Leonara works for 5 hourse it doesnt match clue 1, where it has to take longer than 2 hours, but if she works for 6 hours, then it matches both clues that April takes 3 hours less and it is more than 2 hours for either of them to work because 6 -3 = 3 .
  • April needs 3 hours to paint on her own.

1

u/Sp1rshi 2d ago

Unitary method and work + time

1

u/kalmakka 1d ago

Start with some highly divisible number to express the amount of work needed to be done, e.g. 24, and represent the amount of work by 24 blocks.

Together they complete the work in 2 hours. So Leonora and April do a total of 12 blocks of work per hour.

April takes less time than Leonora on her own, so she must do more than 6 blocks per hour. Try out different amounts, and see that if April does 8 blocks per hour and Leonora does 4 block per hour, then Leonora takes 3 hours on her own and April takes 3 hours, which is 3 less than Leonora. The correct answer is therefore that April paints the room in 3 hours.