২২৪৫১
what is the perimeter of the rectangle with diagonal 10 cm and width 6 cm?
উত্তর
28
সমাধান
The adjacent diagonal, width and length of a rectangle form a right angled triangle where diagonal is the hypotenuse.
So, Diagonal2 = Length2 + Width2
or, Length = √(Diagonal2 - Width2) = √(102 - 62) = √(100 - 36) = 8
So, perimeter = 2(Length + Width) = 2(8 + 6) = 28 cm
২২৪৫২
If Rahim was 32 years old 8 years ago, how old was he x years ago?
উত্তর
40-x
সমাধান
Rahim's present age = 32 + 8 = 40
Rahim's age at x years back = 40 - x
২২৪৫৩
In Dhanmondi Lake the current flows at 3 kilometres per hour. The boatmen takes twice as long to travel upstream between two points as it does to travel downstream between the same two points. In still water what is the speed of the boat?
উত্তর
9 miles per hour
সমাধান
Let the boat speed and current flow be U and V respectively. According to the question, the relative speed of boat downstream (U + V) is twice as that of upstream (U - V).
So, U + V = 2(U - V)
or, U + V = 2U - 2V
or, 2U - U = V + 2V
or, U = 3V = 3 x 3 = 9 km per hour
২২৪৫৪
Which one of the following is equal to 1/4 of 0.01 percent?
উত্তর
0.0025
সমাধান
1/4 of 0.01 %
= 1/4 of 0.01/100
= 0.0025
২২৪৫৫
Jonyh bought a shirt, a pair of pants and a pair of shoes , which cost Tk. 1,000 Tk. 2,000 , and Tk. 3,000 respectively. What percent of the total expense was spent for the pants?
উত্তর
33.33%
সমাধান
Percent of total expense spent for pants = 2000 / (1000 + 2000 + 3000) x 100% = 33.33%
২২৪৫৬
The average of a a, b, c is 6 and a-b =4, ab = 21, What is the value of c?
উত্তর
8
সমাধান
a + b + c = 6 ×3 = 18
( a + b)2 = ( a - b) 2 + 4ab
= 42 + 4 × 21 = 16 + 84 = 100
a + b = 10
10 + c = 18
c = 8
২২৪৫৭
In a village the growth rate of population is 5% every year. There are 1600 people in the beginning of 2008. what will be the approximate number of people in the beginning of 2011?
উত্তর
1,696
সমাধান
The next World Cup Football will be hosted by Russia in 2018 and Qutar in 2022.
২২৪৫৮
In a group of 15 high school students, 7 study Latin, 8 study French, and 3 study neither Latin nor French. How many students study both Latin and French?
উত্তর
4
সমাধান
Number of students studying atleast one language = 15 - 3 = 12
Number of students studying both language = 7 + 8 - 12 = 3
২২৪৫৯
A truck driver must complete a 180-mile trip in 4 hours. If his average speed is 50 miles per hour for the first 3 hours, then how fast must he travel for the final hour?
উত্তর
30
সমাধান
50 × 3 = 150
180 - 150 = 30
২২৪৬০
The surface area of a cubic box is 150 cm2. what is the volume of that box?
উত্তর
125 cm3
সমাধান
rface area of a cubic box is 150 cm2. what is the volume of t
Let the side of the cube be X.
Now, surface area, 6X2 = 150
or, X2 = 25
or, X = 5
So, Volume, X3 = 53 = 125 cm3