ChatterBank0 min ago
Homework Question
Hi all, I was helping my son with homework tonight and had a total brain freeze.
Here's the question:
Mina has 5 more marbles than Kirsty
Kirsty has 2 more marbles than Seb
Altogether they have 30 marbles.
How many does each child have?
I just can't figure out how to work it out.
Here's the question:
Mina has 5 more marbles than Kirsty
Kirsty has 2 more marbles than Seb
Altogether they have 30 marbles.
How many does each child have?
I just can't figure out how to work it out.
Answers
Best Answer
No best answer has yet been selected by xud. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.I must admit I've no idea how maths/algebra is taught these days, but we were always taught that if you have the method correct you could still achieve 8/10 even if you had the wrong answer; whereas if you took an educated guess or just wrote down the answer after doing it in your head you would only attain a 5/10 even with the correct answer.
Does that still apply today?
Does that still apply today?
Captain's also seems fine to me- he was just pointing xud in the right direction. Prudie's is perhaps a little easier to follow up in that the equation to solve contains only additions.
As for the working out, it's always better to include it as you can gain method marks (provided the question is worth more than one mark, and this would be worth 2 or 3) , but you would be given full marks for a correct answer even if you showed no working- unless the question says you must show your working and explain your solution.
As for the working out, it's always better to include it as you can gain method marks (provided the question is worth more than one mark, and this would be worth 2 or 3) , but you would be given full marks for a correct answer even if you showed no working- unless the question says you must show your working and explain your solution.
M = K + 5
K = S + 2
therefore
M = S + 2 + 5
so then
M = S + 7
K = S + 2
and
M + K + S = 30
Solving for S
S = 30 - (M + K)
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
S = 30 - 2S - 9
3S = 30 - 9
S = (30 - 9) / 3
S = 21 / 3
S = 7
K = S + 2 = 9
M = S + 7 = 14
Plugging 7 into the value of S in the above equation
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
confirms our value for S
Interestingly, as it so happens it turns out that M = 2S . . . whatever?
K = S + 2
therefore
M = S + 2 + 5
so then
M = S + 7
K = S + 2
and
M + K + S = 30
Solving for S
S = 30 - (M + K)
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
S = 30 - 2S - 9
3S = 30 - 9
S = (30 - 9) / 3
S = 21 / 3
S = 7
K = S + 2 = 9
M = S + 7 = 14
Plugging 7 into the value of S in the above equation
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
confirms our value for S
Interestingly, as it so happens it turns out that M = 2S . . . whatever?
M = K + 5
K = S + 2
therefore
M = S + 2 + 5
so then
M = S + 7
K = S + 2
and
M + K + S = 30
Solving for S
S = 30 - (M + K)
S = 30 - (S + 2 + S + 7)
S = 30 - 2S - 9
3S = 30 - 9
S = (30 - 9) / 3
S = 21 / 3
S = 7
K = S + 2 = 9
M = S + 7 = 14
Plugging 7 into the value of S in the above equation
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
confirms our value for S
Interestingly, as it so happens it turns out that M = 2S . . . whatever?
K = S + 2
therefore
M = S + 2 + 5
so then
M = S + 7
K = S + 2
and
M + K + S = 30
Solving for S
S = 30 - (M + K)
S = 30 - (S + 2 + S + 7)
S = 30 - 2S - 9
3S = 30 - 9
S = (30 - 9) / 3
S = 21 / 3
S = 7
K = S + 2 = 9
M = S + 7 = 14
Plugging 7 into the value of S in the above equation
S = 30 - (S + 2 + S + 7) = 30 - 23 = 7
confirms our value for S
Interestingly, as it so happens it turns out that M = 2S . . . whatever?