My daughter (in 5th grade) had this math question in her homework. We've not gotten the homework back yet so we don't know if the answer she came up with was right or not. It drove us crazy trying to figure out the logical way to solve it.
3580 / (A x 10) = 89 r20
What is A?
2007-11-07 08:47:35 · 16 answers · asked by sarah 4 in Science & Mathematics ➔ Mathematics
well the (r) is remainder. the question is what is 3580/AX10 that equals 89 with a remainder of 20. what is A? i am not entirely sure what A is...i dont think it works out to be whole number. i think it's somewhere around 3-4. hope that helps.
2007-11-07 08:55:53 · answer #1 · answered by guitarman 2 · 0⤊ 3⤋
3580 / (A x 10) = 89 r20
means:
3580 = (A x 10) x 89 + 20
(in other words, when you divide 3580 by (A x 10) you get 89 with 20 left over)
subtract 20 from both sides:
3560 = A x 10 x 89
multiply out the right hand side:
3560 = A x 890
divide both sides by 890:
4 = A
2007-11-07 16:57:38 · answer #2 · answered by Scott R 6 · 1⤊ 0⤋
A is 4
3580/(a x 10) = 89 r20 = 89 + 20/(a x 10)
multiply both sides by (a x 10) which I am now going to write as 10a and get
3580 = (10a) [89 + 20/(10a)]
this becomes
3580 = 890a + 20 after distributing
subtract 20 and divide by 890 and you get a=4
2007-11-07 16:59:13 · answer #3 · answered by ssssh 5 · 1⤊ 0⤋
Since you had 20 "left over", subtract it from 3580, giving you 3560. Now Multiply both sides of the equation by (A X 10), followed by dividing both sides of the equation by 89. This should give you:
3560/89 = (A X 10)
3560/89 is 40, so the equation is:
40 = (A X 10)
Divide both sides by 10:
4 = A
A little tough for a fifth grader...
2007-11-07 16:57:54 · answer #4 · answered by BAM55 4 · 1⤊ 0⤋
4
2007-11-07 16:53:30 · answer #5 · answered by Anonymous · 1⤊ 0⤋
cool problem!
Ok, without using algebraic notation.....(putting myself back in 5th grade! :)....
"remainder 20" means that
3580 = 89 x (divisor) +20
3580 = 89 x A x 10 +20
3580 = 890 x A +20
3560 = 890 x A
so A = 3560/890 = 4
check: does 3580/40 = 89 r20?
40x89= 3560. Add 20 and you have 3580. yep!
2007-11-07 17:01:36 · answer #6 · answered by Michael M 7 · 1⤊ 0⤋
For starters, you have a remainder of 20. Subtract 20 from both the numerator and the quotient, so you get 3560/(A*10)=89. Then multiply both sides by (A*10) and divide by 89 to get 3560/89=A*10. Then divide by 10 to leave 3560/890=A. 3560/890=4, so A=4. To check, 3560/40=89 r20.
The answer is 4.
2007-11-07 16:58:39 · answer #7 · answered by kaysaw99 2 · 1⤊ 0⤋
Ok well 89r20 = 89 + 20/89 = 7941/89
So...
3580 / (10a) = 7941/89
Multiply both sides by 10a
3580 = (79410/89)a
Multiply both sides by 89/79410
4.01234015 â a
If you test it in the equation, you get â89.22 which is about equal to 89 remainder 20
2007-11-07 16:55:47 · answer #8 · answered by A A 3 · 0⤊ 2⤋
I don't know if this is a good problem for a 5th grader, but sammy is right in his answer of A=4, and the r is for remainder. Good luck.
2007-11-07 17:04:49 · answer #9 · answered by hillbilly 7 · 0⤊ 1⤋
My younger sister often comes to me for homework help and I cant do her maths! She came to me with a practice SATs paper - the pne that I'd done for my actual SATs - and I couldn't do it!
But yeh. Sorry, I'm not sure about the answer.
2007-11-07 16:57:42 · answer #10 · answered by Suite-Pee 6 · 0⤊ 3⤋