Mathematics Questions - Part 01

1) 5 skilled workers can build a wall in 20 days; 8 semiskilled workers can build a wall in 25 days; 10 unskilled workers can build a wall in 30 days; If a team has 2 skilled, 6 semiskilled and 5 unskilled workers, how long will it take to build the wall?
a) 20 days
b) 18 days
c) 16 days
d) 15 days

Correct Answer: D

Let one day work of skilled semi-skilled and unskilled worker be a, b, c units respectively.
   5a×20= 8b×25=10c×30= Total unit of work
            100a= 200b = 300c
                a= 2b= 3c
               b= a/2   and  c= a/3
given that 2 skilled, 6 semi skilled and 5 unskilled workers are working. Let they finish the work in 'x' days.
     ( 2a+3b+5a/3) x = 5a × 20
     20ax/3= 5a×20
          X= 15 days

2) A car travels 8 km in the first quarter of an hour, 6 km in the second quarter and 16km in the third quarter. The average speed of the car in km per hour over the entire journey is?
a) 30
b) 36
c) 40
d) 24

Correct Answer: C

Average speed= Total distance/ total time
Total distance/ total time = (8+6+16) km/ (1/4 + 1/4 + 1/4 ) hrs.
= 40km/ hr

3) Raju has 14 currency notes in his pocket consisting of only Rs. 20 notes and Rs. 10 notes. The total money value of the note is Rs. 230. The number of Rs. 10 notes that Raju has is?
a)    5
b)    6
c)    9
d)    10

   Correct Answer:A

Let the number of Rs. 20 notes be 'a' and Rs. 10 notes be 'b' respectively.

  So,  a+b= 14

        20a+ 10b= 230

On solving a= 9 ,b= 5

Hence the number of Rs. 10 notes are 5

4.    What is the change that a leap year, selected at random, will contain 53 Saturdays?
a)    2/7
b)    3/7
c)    1/7
d)    5/7

Correct Answer:A

Every leap year will have 366 days
1 leap year = 366 days
                    = 52× 7+2 days
Every leap year will have 52 complete weeks. For 53rdSaturday there are two favorable cases from 7 possible cases

Friday               Saturday
Saturday          Sunday
Sunday             Monday
Monday           Tuesday
Tuesday           Wednesday
Wednesday     Thursday
Thursday          Friday

2 favorable cases

Required probability = 2/7

 5.    What is the next number in the series
    12     35    81   173    357   _
a)    725
b)    752
c)    750
d)    758

Correct Answer:A

difference between consecutive terms of the series are

23,46,92,184, _

 That is multiple of 23  with 1,2,4,8 respectively

So the next term will be 357+(23*16)= 725

6.    Find the odd one from the following group:
    WEKO    IQWA    FNTX    NVBD
a)    WEKO
b)    IQWA
c)    FNTX
d)    NVBD

Correct Answer:D

Difference between 1^st and 4^th, 2^nd and 3^rd letters in each series respectively is same expect NVBD

7.    A train that is 280 meters long, traveling at a uniform speed, crosses a platform in 60 seconds and passes a man standing on the platform in 20 seconds. What is the length of the platform in meters?
a)    560m
b)    506m
c)    566m
d)    562m

Correct Answer:A

let the length of the platform is x and velocity of train is v

distance = velocity × time

 (280+ x) = v × 60    (1)

    280     =  v× 20      (2)

From 1 and 2  we get

          X= 560m

8.    Fill in the missing number in the series.
2    3    6    15     _     157.5     630
a)    49
b)    46
c)    43
d)    45

Correct Answer:D

2 , 3 , 6 , 15 , _ , 157.5 , 630

        2× 1.5 = 3

         3× 2   = 6

6× 2.5= 15

15× 3 = 45

         45×3.5=157.5

45 is the missing term of the series

9.    Find the odd one in the following group
QWZB   BHKM    WCGJ    MSVX
a)    QWZB
b)    BHKM
c)    WCGJ
d)    MSVX

Correct Answer:C

adding 6,3, and 2 gives the consecutive letters.

Only c doesn’t follow

10.    The next term in the series  81   54   36   24   _  is ?
a)    4
b)    8
c)    16
d)    12

Correct Answer:C

alternate terms are perfect squares 9^2, 6^2, 4^2 and in between terms are products 9×6

  6×4 and so on missing term is

                 4^2= 16