If p + q = 10 and pq = 5, then the numerical value if p/q

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If p + q = 10 and pq = 5, then the numerical value if p/q + q/p will be ?

1. 22
2. 18
3. 16
4. 20

Correct Option: B

p/q + q/p = (p² + q²)/pq
Apply the formula of algebra
a²+ b² = (a + b)² - 2ab

p/q + q/p = ( (p + q)² - 2pq ) / pq
By substituting the pq and p + q values in given equation.
p/q + q/p = ( (p + q)² - 2pq ) / pq
p/q + q/p = ((10)² - 2 x 5 ) / 5
p/q + q/p = (100 - 10 )/ 5 = 90/5 = 18
p/q + q/p = 90/5 = 18
p/q + q/p = 18