Word problems on Numbers Quiz

1. In a park, there are some cows and some ducks. If total number of heads in the park are 68 and
number of their legs together is 198, then find the number of ducks in the park.
1) 37  2) 47  3) 57  4) 27  5) None of these

Solution: (1).Here, L =198 and H = 68
So, number of cows = (L – 2H) / 2 = (198-2 x 68) / 2
= (198 – 136)/2 = 62/2 = 31
Therefore number of ducks = Number of heads – number of cows
= 68 – 31 = 37

 

2. Five times of a positive integer is equal to 3 less than twice the square of that number. Find the
number.
1) 3  2) 13  3) 23  4) 33  5) None of these
Solutions : (1). Let the number be x
According to the question ,
5x=2x2 – 3
= 2x2 – 5x – 3 = 0
= (x-3) (2x+1) = 0
X=3, - ½
Thus, the required number is 3.

 

3. Find the maximum number of trees which can be planted 20 m apart on the two sides of a straight
road 1760 m long.
1) 174  2) 176  3) 180  4) 178   5) None of these
Solution: (4).Number of trees that can be planted on one side of road = 1760/20 + 1 = 88 + 1 = 89
Therefore trees on the both sides = 2 x 89 = 178

 

4. There are two examination halls P and Q. If 10 students shifted P to Q , then the number of students
will be equal in both the examination halls. If 20 students shifted from Q to P, then the students of P
would be doubled to the students of Q. The number of students would be in P and Q, respective are
1) 60, 40  2) 70,50  3) 80,60  4) 100,80  5) None of these
Solution:( 4). Use the option to solve the sum.

 

5. In a three-digit number, the digit in the unit’s place is four times the digit in the hundred’s place. If
the digit in the unit’s place and the ten’s place are interchanged, the new number so formed is 18 more
than the original number . If the digit in the hundred’s place is one-third of the digit in the ten’s place,
then what is 25% of the original number?
1) 67  2) 84  3) 137  4) Couldn’t be determined  5) None of these
Solution:(1).Let hundred’s digit = x
Then unit’s digit = 4x and ten’s digit = 3x
Number = 100x + 30x + 4x = 134x
Again, hundred’s digit = x
Ten’s digit = 4x and unit’s digit = 3x
Number = 100x + 40x + 3x = 143x
According to the question,
143x – 134x = 18 = 9x = 18
X=2
Therefore original number = 134x = 134 x 2 = 268
25% of original number = 268 * 25/100 = 67