if 70 men dig 15,000 sq. m of a field in 5 days, how many men will dig 22.500 sq. m field in 25 days?
ans-21 men
this is based on the unitary method.
2007-01-09 00:45:52 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
70 men * 5 days means 15 sq. m
x men * 25 days means 22,5 sq. m
70*5/(x*25)=15/22,5
x=350*22,5/(25*15)=21
2007-01-09 00:53:44 · answer #1 · answered by Salih D 1 · 0⤊ 0⤋
This is why I hate abstract math. You would have to assume that ALL of the men could keep the same PACE every day... we all know that is impossible. If the question related to an estimate for a job bid, you would take the 21 men and add 5 giving you 26.
(digging five times longer = 1 extra person for every multiple of time to offset fatigue/injury delays as time goes on) If it is just old fashioned math book problem then 21 would be the "correct" answer.
2007-01-09 09:01:55 · answer #2 · answered by justin h 2 · 0⤊ 0⤋
For the unitary method you first need to find out how much field one man will dig in one day. So, divide the amount of field by the total number of men:
15,000/70=214.28sq m per man in 5 days
and then divide again by the number of days:
214.28/5=42.92 sq m per man per day
now. We need to dig a 22500 sq m field in 25 days. that is equivalent to digging 22500/25 = 900 sq m per day. How many men do we need to do this?
The answer is 900/42.92= 21 men
2007-01-09 09:00:06 · answer #3 · answered by robcraine 4 · 0⤊ 0⤋
the ratio is 70 * 22500/25/15000*5 = 70*0.3 = 21
2007-01-09 09:00:33 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Your answer is correct.
From the initial information...42.9 m^2 per man-day
22,500 m^2 / (25 day * 42.9 m^2 per man-day) = 21 men
2007-01-09 08:57:03 · answer #5 · answered by gebobs 6 · 0⤊ 0⤋
hahaha..try using exponential growth equation..think it'll work..
2007-01-09 08:56:04 · answer #6 · answered by LiquidSilver 3 · 0⤊ 1⤋