Question
The average of three numbers a, b and c is 2 more than
c. The average of a and b is 48. If d is 10 less than c, then the average of c and d is:Solution
Average of a and b = (a + b)/2 ⇒ (a + b)/2 = 48 ⇒ a + b = 96 ----(i) Average of three numbers a, b, and c = (a + b + c)/3 ⇒ (a + b + c)/3 = 12 + c ⇒ a + b + c = 36 + 3c ⇒ a + b = 36 + 2c Using (i), ⇒ 96 = 36 + 2c ⇒ 2c = 60 ⇒ c = 30 Then, ⇒ d = 30 – 10 ⇒ d = 20 Average of c and d = (c + d)/2 ⇒ (30 + 20)/2 ⇒ 50/2 ⇒ 25 ∴ The average of c and d is 25
I. 2x2 – 5x – 63 = 0
II. 2y2 – 7y – 72 = 0
I. 2x² + 11 x + 15 = 0
II. 2y² - 19 y + 44 = 0
I. 3x² - 22 x + 40 = 0
II. 4y² + 22y + 24 = 0
I. y/16 = 4/y
II. x3 = (2 ÷ 50) × (2500 ÷ 50) × 42 × (192 ÷ 12)
Solve the quadratic equations and determine the relation between x and y:
Equation 1: x² - 42x + 392 = 0
Equation 2: y² - 46y + 480 = 0
I. x2 – 9x + 18 = 0
II. y2 – 5y + 6 = 0
I: x² - 10x + 21 = 0
II: 4y² - 16y + 15 = 0
I. p2 +7p + 10 = 0 II. q2 - q – 6 = 0
I. 2x2 – 25x + 33 = 0
II. 3y2 + 40y + 48 = 0
I. x2 + 28x + 96 = 0
II. y2 + 3y - 70 = 0
