Ans 1. suppose pipe A alone takes x hours to fill the cistern
. . B alone takes ( x+ 6) hours to fill the cistern.
Ans 2. In 150 kg of wheat , there is 135 kg of good quality wheat and 15kg of inferior quality wheat.
Let x kg of good quality wheat be mixed in 135 kg good quality wheat so that the total quantity of good quality wheat becomes 95% of the total wheat.
i.e. , 95% of ( 150 + x).
. . 135 + x = 95% of ( 150 + x)
i.e. x = 150
Ans 3. L.C.M of 5,6,7,8 = 840 k + 3
Least value of K for which ( 840 k + 3) is divisible by 9 is k = 2
. . Required number = ( 840 x 2 + 3) = 1683
Ans 4. Total number of oranges = 12
The number of bad oranges = 12 x 1/3 = 40
. . number of good oranges = 12 -4 = 8.
Now, the total number of ways of selecting 3 oranges from the box = 12c3.
The Total number of ways of selecting 3 bad oranges out of 4 bad oranges = 4C3
Hence, the probability of selecting all the three bad oranges ( no good oranges )
= 4C3/12C3 = 1/55
Therefore, the probability of selecting at least one good orange = 1 - 1/55 = 54/55\
Ans 5. Let their initial investment be x, 3x, 5x Then
A : B : C = x x 4 + 2 x x 8 : 3x x 4 + 3x/z x 8 : 5x x 4 + 5x/2 x 8
= 20x : 24x : 40x = 5 : 6 : 10.
Ans 6. Let the salaries of A,B and C be x , y , z respectively
. .
Ans 7. To earn Rs. 135, investment = Rs 1620
To earn Rs 8, investment
. . Mraket value of rs. 100 stock = Rs 96.
Ans 8.
Ans 9. 26th January , 1950 means.
= ( 1949 years+ period from Ist January to 26th January)
Number of odd days in ( 1600 + 300) years
= ( 0 + 1) = 1
49 years = ( 12 leap years + 37 ordinary years) = ( 24 + 37) odd days = 61 odd days = 5 odd days
26 days of January have 5 odd days.
, . Total number of odd days = ( 1 + 5 + 5)
4 odd days
The desired day was = Thursday.
Ans 10.Let at man's one day wage be M and a boy's one day wage be B.
. . 3M + 4B= 756/7 = 108
and 11M + 13B = 3008/8 = 376
solving the two equations , we get wage of a man for a days work = rs 20& wage of a boy a day's work = Rs 12.
. . Combined wages of 7 men + 9 boys for a day ;s work = 140 + 108 = Rs. 248
No. of days required = 2480/248 = 10 days.
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