Answer:
(1) C
(2) D
(3) B
(4) B
(5) C
Step-by-step explanation:
(1) % decrease = change in price/initial price × 100 = (25 -20)/25 × 100 = 5/25 × 100 = 20
(2) Number of correct answers he answered in the second test = 150 + (30/100 × 150) = 150 + 45 = 195
(3) Let the number be y
3(y + 2) = 24
y + 2 = 24/3 = 8
y + 2 = 8
y = 8 - 2 = 6
(4) Let my father's age be f, my brother's age be b and my age be m
From the first statement
f/5 = b/3 ----- eqn (1)
From the second statement
b = m + 3 ----- eqn (2)
From the third statement
f = 2m - 3 ------ eqn (3)
Substitute the expression of b and f in eqn 2 & 3 into eqn 1
(2m - 3)/5 = (m + 3)/3
3(2m - 3) = 5(m + 3)
6m - 9 = 5m + 15
6m - 5m = 15 + 9
m = 24
Substitute the value of m into eqn 3
f = 2m - 3 = 2(24) - 3 = 48 - 3 = 45
(5) (x - 2)/4 - (3x + 5)/7 = -3
The LCM of 4 and 7 is 28
Multiply each term in the equation by 28
7(x - 2) -4(3x + 5) = -3(28)
7x - 14 - 12x - 20 = -84
-5x - 34 = -84
-5x = -84 + 34
-5x = -50
x = -50/-5 = 10
