# Silver, one of the first 'metal' used by 'humans' is an 'excellent' conductor of heat and 'electricity'.

metal

humans

excellent

electricity

### Description (বিবরণ) :

প্রশ্ন: Silver, one of the first 'metal' used by 'humans' is an 'excellent' conductor of heat and 'electricity'.

ব্যাখ্যা:

প্রশ্নে ভুল অংশটি হলো option a. One of the + plural noun বসে। তাই  metal-এর স্থলে সঠিক word হবে metals।

## If x:y = 5:3 then (8x-5y):(8x+5y) = ?

3:12

8:13

3:11

5:11

5:13

Description (বিবরণ) :

Hints: x/y = 5/3

8x/5y = 8✘5/5✘3

8x-5y /8x+5y = 40-15 / 40 +15 = 25/58 =5/11 =5  : 11

## A toy was bought for Tk 75 and sold at a gain of 8%. What was its selling price in Tk ?

78

81

80

84

85

Description (বিবরণ) :

Hints: Selling price at 8% gain = 75 + 75✘8/100= 75+6=81

## If a man's salary is 20% more than that of his son, how many percent is the son's salary if compared to the salary of his father ?

75

80

83

85

87

Description (বিবরণ) :

Hints: Let main's salary = m,  son's = s

m = s+ s ✘. 20 = 1.20S

s= m/1.20 ✘ 100% = 83.33%

## A woman is 30 times older than her son. 18 years later she will be thrice as old as her son. What is the woman's present age in years ?

30

35

36

40

48

Description (বিবরণ) :

Hints: Let woman's age = w sons  = s

w = 30 s

এবং,  w+18 = 3(s+18)

w +18 =3s +54

10w +180 =30s +540 [10 multiplication by both side]

10w +180 =w+540

9w =540 -180

9w =360

w= 40 (ans)

## If x men can do a work in 8 days and x+4 men can do it in 6 days, what is the value of x ?

4

6

8

12

16

Description (বিবরণ) :

Hints: x জন করে  8 দিনে

1  জন করে 8x দিনে

(x+4)  জন করে 6 দিনে

1 জন করে   6(x+4)  দিনে

এখন,  8x =6x +24

2x =24

x = 12