Bart had 57 less madeleines than Jeff. Bart saved 3/5 of his madeleines while Jeff spent 2/3 of the madeleines. Given that the amount Bart spent was 1/4 of Jeff’s savings, how much did Jeff spend?
Let the number of madeleines with Jeff be 'j' and the number of madeleines with Bart be 'b'.
Then, if Bart had 57 fewer madeleines than Jeff: \(b = j - 57 …1\)
Given, Bart saved 3/5 of his madeleines.
He must have spent the rest:
\(1\)\(-\)\({3 \over 5}\frac{}{}\)\( = {2\over 5}\frac{}{}\)
Bart's spending =\( {2 \over 5}b\frac{}{}\)
If Jeff spent 2/3 of his madeleines.
He must have saved the rest:
\(1 - \)\( {2 \over 3}={}{}\)\({1 \over 3}\frac{}{}\)
Jeff savings=\( {1 \over 3}\frac{}{}\)
Given: the amount Bart spent was 1/4 of Jeff’s savings.
Thus,
\( {2 \over 5}{}{}\)\(b\)\(=\)\({1 \over 4}{}{} \)\((\)\( {1 \over 3}j{}{}\)\()\)
Cross multiply:
2 * 4 * 3 * b = 1 * 5 * j
24b = 5j ...2
Solve using equation 1 and equation 2:
\(b = j - 57 …1\)
\(24b=5j …2\)
\(24(j-57) = 5j\)
\(24j-1368=5j\)
\(19j=1368\)
\(j = {1368 \over 19}{}^{}=72\)
Hence, Jeff had 72 madeleines originally.
The question is how much did Jeff spend:
Given, Jeff spent 2/3 of the original value: \( {2 \over 3}{}{} * 72 = 48\)
Jeff spent 48 madeleines.
Let the number of madeleines with Jeff be 'j' and the number of madeleines with Bart be 'b'.
Then, if Bart had 57 fewer madeleines than Jeff: \(b = j - 57 …1\)
Given, Bart saved 3/5 of his madeleines.
He must have spent the rest:
\(1\)\(-\)\({3 \over 5}\frac{}{}\)\( = {2\over 5}\frac{}{}\)
Bart's spending =\( {2 \over 5}b\frac{}{}\)
If Jeff spent 2/3 of his madeleines.
He must have saved the rest:
\(1 - \)\( {2 \over 3}={}{}\)\({1 \over 3}\frac{}{}\)
Jeff savings=\( {1 \over 3}\frac{}{}\)
Given: the amount Bart spent was 1/4 of Jeff’s savings.
Thus,
\( {2 \over 5}{}{}\)\(b\)\(=\)\({1 \over 4}{}{} \)\((\)\( {1 \over 3}j{}{}\)\()\)
Cross multiply:
2 * 4 * 3 * b = 1 * 5 * j
24b = 5j ...2
Solve using equation 1 and equation 2:
\(b = j - 57 …1\)
\(24b=5j …2\)
\(24(j-57) = 5j\)
\(24j-1368=5j\)
\(19j=1368\)
\(j = {1368 \over 19}{}^{}=72\)
Hence, Jeff had 72 madeleines originally.
The question is how much did Jeff spend:
Given, Jeff spent 2/3 of the original value: \( {2 \over 3}{}{} * 72 = 48\)
Jeff spent 48 madeleines.
Let $a_1$ equal Bart's madeleines, and let $a_2$ equal Jeff's madeleines.
$a_1 + 57 = a_2$
$\left(1-\frac{3}{5}\right) a_1 = \frac{1}{4} \cdot \left(1-\frac{2}{3}\right) a_2$
$\frac{2}{5} a_1 = \frac{1}{12} a_2$
$24 a_1 = 5 a_2$
$24 a_1 = 5(a_1 + 57)$
$24 a_1 = 5 a_1 + 5 \cdot 57$
$19 a_1 = 5 \cdot 57$
$a_1 = \frac{5 \cdot 19 \cdot 3}{19}$
$a_1 = 15$
$a_2 = 15 + 57 = 72$
$\frac{2}{3} a_2 = \frac{2}{3} \cdot 72 = 24 \cdot 2 = \boxed{48}$