Can someone help with this question pls :
May has $27 of coins in her piggy bank. The coins were a mixture of 20-cents and 50-cents. There were half as many 50-cents coins as 20-cents. How many 50-cents coins were there in the piggy bank?
Thanks
2007-02-05 21:15:33 · 6 answers · asked by Fern 3 in Science & Mathematics ➔ Mathematics
20-cent coins: x
50-cent coins: x/2
(0.20)x + (0.50)(x/2) = 27
0.20 x + 0.25 x = 27
0.45 x = 27
x = 60
60 20-cent coins, 30 50-cent coins.
2007-02-05 21:34:55 · answer #1 · answered by Mathematica 7 · 0⤊ 0⤋
Let number of 20 cent coins = x and number of 50 cent coins = y
20x + 50y = 2700
20x + 50 (x/2) = 2700
20x + 25x = 2700
45x = 2700
x = 2700 / 45 = 540 / 9 = 60
There are 60 of the 20 cent coins
There are therefore 30 of the 50 cent coins
2007-02-06 05:43:17 · answer #2 · answered by Como 7 · 0⤊ 0⤋
Let T be the number of 20-cent coins, and F be the number of 50-cent coins. Then the dollar amount of all her 20-cent coins should be 0.20T and the follar amount of the 50-cent coins should be 0.50F.
We're told she has $27 in total, so 0.20T + 0.50F = 27. We're also told that she has half as many 50-cent coins as she has 20-cent coins. So F = T/2. Now you've got two equations with two unknowns. Solve for F and T. (Hint: plug F=T/2 into the first equation and solve for T, then use F=T/2 to solve for F)
2007-02-06 05:39:43 · answer #3 · answered by Anonymous · 0⤊ 0⤋
$27 = .50 X + .20 (2X)
$27 = .50x + .40x
$27 = .90x.....divide both sides by .90
30= x
30 fifty cent pieces = $15
60 twenty cent pieces = $12
15+12= well minus the dollar for my coca cola - is 26
2007-02-06 05:26:34 · answer #4 · answered by tom4bucs 7 · 1⤊ 0⤋
Are there such things as 20 cent pieces? Anyway, there are 30 50-cent pieces. 60*0.20=$12.00 30*0.50=$15.00. $15.00+$12.00=$27.00. Hope this helps.
2007-02-06 05:35:13 · answer #5 · answered by rich_a73 1 · 0⤊ 0⤋
x=20 cents coins
y=50 cents coins
y=x/2
so x=2y
but x+y=27
and 2y+y=27
so y=9
then x=18
2007-02-06 05:23:46 · answer #6 · answered by ioana v 3 · 0⤊ 2⤋