Directions (46-47): Read the following quadric equation carefully and answer the questions given below.
Equation 1:
Equation 2:
Note:
(i) c is a single digit prime number greater than 2
(ii) d and b are two digits prime number less than 20
(iii) d is greater than 11
(iv) b is greater than d
(v) Smallest roots of both the equation are same
(vi) No root is irrational
(vii) e = b + 1
(viii) 3c is greater than b
Find the value of ‘d× e’ .
Correct Answer :
260
Solution :
The correct answer is 260.
Step-by-step Explanation:
Let's analyze the given conditions step-by-step to find the values of the variables:
1. Identify the possible values of , , and :
- From note (i), is a single-digit prime number greater than 2. The prime numbers meeting this condition are:
- From note (ii), and are two-digit prime numbers less than 20. The prime numbers meeting this condition are:
- From note (iii), is greater than 11. Therefore, can be:
- From note (iv), is greater than (). This implies cannot be 19. Thus, can be 13 or 17, and can be 17 or 19.
2. Apply the condition :
- From note (viii), we have .
- Since the maximum possible value of is 7, we have .
- For to hold, let's test the possible values:
If , then . The only prime value for that satisfies this is (since ).
- If , then since and , can be 13 or 17.
3. Use the quadratic equations and their roots to narrow down:
- Note (vii) states that .
- If , then:
- Let's test the value of :
Equation 2 becomes:
- Solving this quadratic equation:
The roots are and .
Since , the smallest root of Equation 2 is .
- According to note (v), the smallest roots of both equations are the same, so must be the smallest root of Equation 1:
Substitute , , and :
- Let's check Equation 1 with :
The roots are and .
The smallest root is indeed , and neither root is irrational, satisfying all constraints.
4. Calculate the value of :
Using and :
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