There are 15 machines in a factory.A worker takes 10 minutes to start up one machine.The first machine starts at 2:00 p.m. and so on. Each machine produces 2 kg of machine in 5 minutes.All machines stop production at 6:00 p.m.
a) Find the production time in minutes for the first second and third machines each from 2:00 p.m. to 6:00 p.m.
b) Find the production time in minutes for the last machine from 2:00 p.m. to 6:00 p.m.
c)find the weight of material in kilograms produced by all the machines from 2:00 p.m. to 6:00 p.m.
[F.6 MATH] Arithmetic Sequence Application?
2016-09-08 2:44 pm
回答 (2)
2016-09-08 8:59 pm
✔ 最佳答案
(a)Let Tn denote the production time in min. for the n-th machine
T1 = (6-2)*60 = 240
T2 = 240 - 10 = 230
T3 = 230 - 10 = 220
(b)
Tn = 240 - 10( n - 1 )
T15 = 240 - 10( 15 - 1 ) = 100
(c)
2*(240/5) + 2*(230/5) + ...... + 2*(100/5)
= (2/5)( 240 + 230 + ...... + 100 )
= 0.4 * (240+100)*15/2
= 1020
Ans :
(a) 240, 230 and 220 min respectively.
(b) 100 min
(c) 1020 kgs
2016-09-08 6:20 pm
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