A certain machine fills jars of molasses by drawing molasses at a cons

Question

A certain machine fills jars of molasses by drawing molasses at a constant rate from a supply tank that holds l liters of molasses when full. If the machine draws m liters of molasses from the supply take in s seconds and no additional molasses is added to the tank, how many minutes will it take the machine to empty a full supply tank?

A. l−60m/s

B. 60ls/m

C. 60lm/s

D. m/(60ls)

E. ls/(60m)

A. l−60m/s
 
B. 60ls/m
 
C. 60lm/s
 
D. m/(60ls)
 
E. ls/(60m)

zmtalha · Answer

S seconds =  \frac{s}{60}  minutes
M liter in  \frac{s}{60}  minutes
So, L liter in  \frac{Ls}{60m}  minutes
Ans: E

Luckisnoexcuse · Answer

s Seconds to empty m litres
1 second to empty m/s litres
1 minute to empty 60m/s litres
60 m/s litres get emptied in 1 min
1 litre gets empties in s/60m mins
l litres get empties in sl/60m mins
E

MvArrow · Answer

Can someone explain what I am doing wrong?

A = RT so... L =  T .... L = (M/60S)T ..... T = 60SL/M hence B...

zmtalha · Answer

From 2nd line to 3rd line, you wrote  L=\frac{m}{(s/60)}*T  to  L = \frac{M}{60S}*T , It should be  L=\frac{60m}{s}*T

generis · Answer

I picked numbers, centered around 60 secs/min. Tank capacity   l   is a multiple of 60. Drain amount   \frac{m}{s}   divides easily into 60.

Let   l = 600   
Let   m = 5  
Let   s = 1

Rate is   \frac{5l}{1s}*\frac{60s}{1min}=\frac{300l}{1min}

\frac{W}{r}=t

\frac{600L}{(\frac{300L}{1min})}= 600L* \frac{1min}{300L}= 2 min

With   l = 600  ,   m = 5  , and   s = 1  , find the answer choice where time taken = 2 minutes

Immediately eliminate answers A, B, C, and D.

For (A) and (C),   s = 1  : That tiny denominator would require a numerator of 2. But   l =600  , in the numerators, is huge. Not even close.

For (B) and (D):   m = 10  : That is too small a numerator to have   l = 600   in the denominator. By POE, E remains.

E. ls/(60m)
  \frac{(600*1)}{(60)(5)}=\frac{600}{300}=2  . That is a match.

Answer E

chetan2u · Answer

in substitution, it will be easier calculations if you pick up some numbers accordingly..

let the capacity be 100 ltrs, so l = 100
let m be 100 in 60 secs, so s= 60 secs or 1 min..
our answer should be entire 100 in 1 min
look for choice that gives you 1 as answer..

E.. ls/(60m) = 100*60/60*100=1

generis · Answer

Originally I agreed with you. Thank you (and kudos) for laying out an alternative. I originally used (l = 600), (m = 10), (s = 1). Same result as yours: 1 minute to drain tank. I ran the numbers again, slightly changed, in order to be sure, and because occasionally the seconds-to-minutes conversion gives me pause. The second set of numbers, with m a little smaller (5 instead of 10), seemed to eliminate answers more obviously. Maybe not true for others; but it worked for me. Thanks again.

JeffTargetTestPrep · Answer

The rate of the machine drawing molasses from the tank is m/s liters per second or 60 * (m/s) = (60m)/s liters per minute. Since the supply tank can hold l liters of molasses when it’s full, it will take the machine l/(60m/s) = l * (s/60m) = ls/(60m) minutes.

Answer: E

MHIKER · Answer

RT=W

\frac{s}{60}T=m

T=\frac{60m}{s}

Now, equating:  \frac{60m}{s}=\frac{l}{x}

x=\frac{ls}{60}

The answer is  E

bumpbot · Answer

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A certain machine fills jars of molasses by drawing molasses at a cons

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A certain machine fills jars of molasses by drawing molasses at a cons

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