Question 1. What is the value of (-21)-[(-23)-(-17)-(-21)].
Question 2. What should be subtracted from -9876 to obtain -9512?
Question 3. Fill in the blanks
i)Sum of integer and
its additive inverse is
____________
ii)Sum of -22 and -44 is
______________
iii) -36 ÷ (_______)=-9
iv) _________ is absolute
value of -998
Question 4. Verify the following
i) (-22) × [(-4) + (-5)]=[(-22) × (-4)] + [(-22) × (-5)]
ii) (-12) × [(3) + (-9)]=[(-12) × (4)] + [(-12) × (-9)]
Question 5. Evaluate
i) (-100)÷5 ii)(-36)÷(-4) iii)(0)÷(-12)
iv) [(-30)÷5]÷2
Question 6. In a test (+5) marks are given for every correct answer and (-2) marks are given
for every incorrect answer.
i)Radhika answered all the questions and scored 30
marks and get 10 correct .
ii)Jay also answered all the
questions and scored (-12) marks though he got 4 correct.
How many incorrect answers had they attempted?
Question 7. In a test (+5) marks are given for every correct answer and (-2) marks are given
for every incorrect answer and 0 for answer not attempted. Ram gets 3 correct and 4
incorrect out of 7 questions he attempted. What is his score?
Answers
Answer:
Your answer are :
1. ( -21 ) - [ ( -23 ) - ( - 17 ) - ( -21 ) ]
= ( -21 ) - [ -23 + 17 + 21 ]
= ( -21 ) - [ 15 ]
= - 36 ( ans. )
2. -9876 - x = -9512
=> x = 9512 - 9876
=> x = - 364 ( ans. )
3.
(i) is always 0 [ x + (-x) = 0 ]
(ii) -22 + ( -44 ) = -22 - 44 = -66
(iii) -36 ÷ x = -9 => x = -36÷(-9) = 4
(iv) -1000 is the absolute value of -998 .
4.
(i) ( -22 ) × [(-4) + (-5)] = LHS = ( -22 ) × ( -9) = 198
RHS = [(-22) × (-4)] + [(-22) × (-5)] = [88] + [110] = 198
hence , LHS = RHS = 198 ( verified )
(ii) same as (i) ; LHS = 72 and RHS = 72 ( verified )
5.
(i) -100/5 = -20
(ii) -36/(-4) = 9
(iii) 0/(-12) = 0
(iv) [(-30)/5]/2 = -6/2 = -3
6.
Given that, +5 marks for correct and -2 for incorrect, keeping in mind these ,
Let, the number of incorrect answers of each candidate is x .
i) For Radhika:
correct = 10
incorrect = x ( as I mentioned above )
total = 30
now , ATQ,
10(5) + x (-2) = 30
=> 50 - 2x = 30
=> -2x = -20
=> x = 10 ( number of incorrect answers ) (Ans.)
(ii) For Joy:
correct : 4
incorrect : x ( as I mentioned above )
total : -12
Now, ATQ,
=> 4(5) + x(-2) = -12
=> 20 - 2x = -12
=> 2x = 32
=> x = 16 ( number of incorrect answers ) (Ans.)
7.
This question is much similar to above ,
For correct : ( +5 )
For incorrect : (-2)
For unattempted : 0
For Ram :
correct = 3
incorrect = 4
total questions are 7 . so, he fully attempt the paper .
his total mark : 3(5) + 4(-2) = 15 - 8 = 7 (ANS.)
Hope it helps