51) ______ is used as a fire extinguisher.
(A) Carbon dioxide
(B) Oxygen
(C) Hydrogen
(D) Nitrogen
52) Isotopes are atoms of the same element with different numbers of:
(A) electron
(B) proton
(C) neutron
(D) positron
53) The most reactive metal is:
(A) Indium
(B) Francium
(C) Manganese
(D) Iridium
54) Which from the following is not a conductor?
(A) Copper
(B) Silicon
(C) Graphite
(D) None of these
55) If x-y=6 ad x+y=16 Then?
(A) x=5 and y=3
(B) x=8 and y=5
(C) x=10 and y=3
(D) x=11 and y=5
56) If A completes a particular work in 10 days, and B completes the same work in 15 days while working separately. Then how many days they will take in working together?
(A) 6
(B) 5
(C) 7
(D) 8
57) |_4| + (-4)1 + (-4)2=?
(A) 0
(B) 1
(C) 8
(D) 16
58) The price of sugar increases by 32%. A family reduces its consumption so that the expenditure of the sugar is up by 10% only. If the total consumption of sugar before the price rise was 10 kg per month, then the consumption of sugar per month at present (in kg) is:
(A) 8.33
(B) 8.5
(C) 8.75
(D) 9
59) A ball pen factory decided to reduce its production by 10% over that of previous month for next 3 months starting from February 1994. In January 1994, it produced 3000 ball pens.How many ball pens were produced in March 1994?
(A) 2700
(B) 2430
(C) 2187
(D) 2400
60) A building worth Rs. 133,100 is constructed on land worth Rs.72,900. After how many years will the value of both be the same if land appreciates at 10% p.a and building depreciates at 10% p.a?
(A) 2.5
(B) 2
(C) 1.5
(D) 3