Question

Saeed bought 21 1/2 lb of ground beef. He used 1/4 of the beef to make tacos and 2/3 of the remainder to make quarter-pound burgers. How many burgers did he make?

Answer 1

Step 1

Convert mixed number to an improper fraction

$21\frac{1}{2}\ lb= \frac{21*2+1}{2} =\frac{43}{2}\ lb$

Step 2

Find the total pounds used in tacos

we know that

Saeed used $1/4$ of the beef to make tacos

so

$\frac{1}{4}*\frac{43}{2}=\frac{43}{8}\ lb$

Step 3

Find how many burgers did Saeed make

we know that

Saeed used $2/3$ of the remainder to make quarter-pound burgers

Remember that

If Saeed used $1/4$ of the beef to make tacos

then

the remainder is $3/4$ of the beef

so

$remainder=\frac{3}{4}*\frac{43}{2}=\frac{129}{8}\ lb$

Multiply the remainder by $2/3$

$\frac{2}{3}*\frac{129}{8}=\frac{129}{12}\ lb$

Divide by $1/4$ to find the number of burgers

$\frac{(129/12)}{(1/4)} =\frac{129}{3}=43\ burgers$

therefore

the answer is

$43\ burgers$

Answer 2

21 and 1/2=21 and 2/4
minus 1/4
21 and 1/4
convert to improper fraction
85/4

2/3 of remainder
2/3 times 85/4=85/6, quarter pound burgers
times 4
170/3
56.6666
can make 56 burgers