Tag: addition & subtraction

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Questions Related to addition & subtraction

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

A 3-digit number 4a3 is added to another 3-digit number 984 to give the four-digit number 13b7 which is divisible by 11 Then (a + b) is

  1. 10

  2. 11

  3. 12

  4. 15
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

According to the question
$4 a 3 + 9 8 4 = 1 3 b 7$
$a + 8 = b$
Then$b - a = 8$
According to the question  13b7 is divisible by 11
$(7 + 3) - (b + 1) = (9 - b)$
$(9 - b) = 0$
$b = 9$
$b = 9   and   a = 1$
Then $a+b=9+1=10$

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

In an examination, a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer. If she attempts in all 50 questions and scores 120 marks, the number of questions she attempts correct is........

  1. 62

  2. 44

  3. 42

  4. 34
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let student get x correct answer then 50-x student get wrong answer 
Then 4(x)+(50-x)(-1)=120
Or 4x-50+x=120
Or 5x=120+50=170
Or x=34

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

If the sum of two consecutive odd numbers is 2004, then the smaller of the two numbers could be

  1. 2001

  2. 1001

  3. 1003

  4. 1
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the two consecutive odd numbers are x and x+2
$x+x+2 = 2004$
$x+x+2-2 = 2004 -2 $ (Subtract 2 from both the sides)
$2x = 2002$
$\frac{2x}{2} = \frac{2002}{2}$ (Divide 2 from both the sides)
$x = 1001$
Hence two numbers are 1001 and 1003

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

A man can row 16 km downstream in one hour but upstream he takes twice the time then the speed of the current is

  1. 8 km/h

  2. 12 km/h

  3. 4 km/h

  4. 2 km/h
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The man down stream is 16 km in one hour and he take twice time in upstream 

Then he take time 2 hour in 16 km 
So speed in upstream =$\frac{16}{2}=8 km /hr$
Then current spread =$\frac{16-8}{2}=4$ km/hr 

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

If a=2, b=3, c=4, then the difference between $\displaystyle 2\frac{3}{4}$ and $\displaystyle b\frac{a}{c}$ is

  1. $-1/4$
  2. $1/4$
  3. $-3/4$
  4. $5/4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If a=2 ,b=3 and c=4

Then $b\tfrac{a}{c}=3\tfrac{2}{4}=3\tfrac{1}{2}$
Then difference between=$2\tfrac{3}{4}-3\tfrac{1}{2}=\frac{11}{4}-\frac{7}{2}=\frac{11-14}{4}=\frac{-3}{4}$

Multiple choice maths operations adding and subtracting numbers using place value addition & subtraction mental additions and subtractions

The average weight of 7 men is diminished by 3 kg when one of them who weighs 73 kg is replaced by a new man then the weight of the new man is 

  1. 50 kg

  2. 52 kg

  3. 53 kg

  4. 54 kg
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The averages weight of seven man diminished by 3 kg .Then total weight diminished by $3\times 7=21 kg $

If one of them whose weight is 73 kg is replased by anew man 
Then weight of new man =72-21=52 kg