It takes a cook 3 minutes 45 se to make 3 sandwiches and 3 salads. it takes him 8 min 30 sec to make 6 sandwiches and 8 salads. How long does it take to make each sandwich?
A 30 sec
B 35 sec
C 45 sec
D 60 sec
I have to idea how to do this
+14985 It takes a cook 3 minutes 45 se to make 3 sandwiches x and 3 salads y. it takes him 8 min 30 sec to make 6 sandwiches x and 8 salads y. How long does it take to make each sandwich x ?
A 30 sec
B 35 sec
C 45 sec
D 60 sec
\(3x+3y=225sec\) [ * 8
\(6x+8y=510sec\) [ * 3
\(24x+24y=1800sec\)
\(18x+24y=1530sec\)
\(1800sec-24x=1530sec-18x\)
\(-6x=-270sec\)
\(x=45sec\)
The cook needs to make a sandwich 45 sec.
!
+129840 3 min 45 sec = 225 sec
8min 30 sec = 510 sec
If it takes 225 sec to make 3 sandwiches and 3 salads, it should only take 225//3 = 75 sec to make 1 sandwich and 1 salad
So let x be the time [ in seconds] to make 1 sandwhich and y be the time [ in seconds] to make 1 salad....and we have this system
1x + 1y = 75
6x + 8y = 510 multiply the first equation by − 6 and add it to the second
2y = 60 divide both sides by 2
y = 30 sec for a salad
And
1x+ 30 = 75 → x = 45 sec for a sandwich
