Question

1. The price of a book decreased from #25 to #20. By how many percent did the price decrease?

Answer 1

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