A certain product have to pass three machines A, B, C in turn to be made.
The time when it takes to pass A, B, C is one minute, two minutes and four minutes respectively.
The next product should wait in front of respective machines until the previous product finishes passing.
Answer the following questions.
(1) Find the number of products completed to be made 25 minutes later from machines began to move.
(2) Find the number of products which finished passing B and are waiting in front of C three hours and six minutes later from machines began to move.
Answer
(1) 5 pieces
(2) 46 pieces
Solution
(1) It is 1 + 2 + 4 = 7 minutes later that the first product finishes passing C.
Answer
(1) 5 pieces
(2) 46 pieces
Solution
(1) It is 1 + 2 + 4 = 7 minutes later that the first product finishes passing C.
Thereafter, a product is completed every four minutes.
(25 - 7) / 4 = 4 remainder 2, therefore 1 + 4 = 5 pieces.
(2) It is 1 + 2 = 3 minutes later that the first product finishes passing B.
Thereafter, a product passes B every two minutes.
The number of products passed B in three hours and six minutes is 1 + 91 = 92 pieces according to (3 × 60 + 6 - 3)/2 = 91 remainder 1.
In addition, the number of products passed C is 1 + 44 = 45 pieces according to (3 × 60 + 6 - 7) /4 =44 remainder 3.
Moreover, there is one product under passing C.
Therefore, the number of products waiting in front of C is 92 - (45 + 1) = 46 pieces.
