00:01
Working together a chef and his assistant can make a pastry dessert in 27 minutes.
00:06
When the chef makes it by himself it takes him five minutes less than the time it takes his assistant working alone.
00:15
How long does it take the chef to make the dessert? so we know that the chef plus the assistant is equal to 27 minutes and the chef makes it by himself.
00:34
So when the chef makes it by himself it is five minutes less than his assistant working alone.
00:42
So a minus five.
00:46
Assistant's time minus five minutes equals the chef's time.
00:50
Chef plus assistant equals 27.
00:55
So what we're going to do now is go ahead and substitute.
00:58
So we know what this c is equal to in terms of a.
01:03
So we're going to plug in for here.
01:05
So a minus five plus a equals 27.
01:12
We're going to get the a's on a side by itself.
01:16
So we are going to add five to both sides...