Question Details

Consider the following inequalities


                                                                  π‘Β² βˆ’ 4π‘ž < 4

                                                                 3𝑝 + 2π‘ž < 6

where 𝑝 and π‘ž are positive integers.

The value of (𝑝 + π‘ž) is _______.

Options

A

2

B

1

C

3

D

4

Show Answer

Correct Answer :

Option A

2

Solution :

The correct answer is 2.

As shown in the provided image, we are given two inequalities involving positive integers p and q:
1) Inequality 1: p2-4q<4
2) Inequality 2: 3p+2q<6

Let's analyze and combine these inequalities step-by-step to find the positive integer values of p and q.

Step 1: Rearrange Inequality 1
We can isolate the term containing q on one side. By adding 4q and subtracting 4 from both sides, we get:

p2-4<4q

Let this be Inequality (i).

Step 2: Rearrange Inequality 2
To align the q terms so they can be eliminated or compared easily with Inequality (i), we can multiply the second inequality by 2:

2(3p+2q)<2(6)

6p+4q<12

Now, isolate the term -4q by subtracting 4q and 12 from both sides:

6p-12<-4q

Let this be Inequality (ii).

Step 3: Combine Inequality (i) and Inequality (ii)
Adding Inequality (i) and Inequality (ii) side-by-side allows us to eliminate the q terms:

(p2-4)+(6p-12)<4q+(-4q)

p2+6p-16<0

Step 4: Factor and solve the quadratic inequality for p
We can factor the quadratic expression by finding two numbers that multiply to -16 and add to 6. These numbers are 8 and -2:

(p+8)(p-2)<0

This inequality holds true when the variable p lies between the two roots of the quadratic equation:

p∈(-8,2)

Since the problem states that p must be a positive integer, the only possible value for p in the interval (-8,2) is:

p=1

Step 5: Solve for q
Now we substitute p=1 back into our inequalities to determine the value of q.

From Inequality (i):

12-4<4q

-3<4q⇒q>-34

From Inequality (ii) or directly from the original Inequality 2:

3(1)+2q<6

3+2q<6β‡’2q<3β‡’q<32

Combining these bounds for q gives:

-34<q<32

Since q is also a positive integer, the only integer in this interval is:

q=1

Step 6: Calculate p+q
Using our values p=1 and q=1:

p+q=1+1=2

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