২২৩৮১
The circumference of a wheel is 6.25 meters. How many cycles will it make in order to cover a distance of 40km?
উত্তর
6400
সমাধান
Circumference of the wheel = 6.256.25 mDistance = 40 = 40 km = 40000 = 40000 mRequired number of cycles = 400006.25 = 6400
২২৩৮২
In how many years amounts of money will treple itself at a simple rate of interest is 20% per annum?
উত্তর
10
সমাধান
Let the principle be tk. x.
So total amount = tk. 3x.
so,interest = 3x - x = 2x
২২৩৮৩
A woman says, "If you reverse the digits my age, the figures represent my husband's age. He is senior to me and the defference between our ages is one-eleventh of their sum. "What is her age now?
উত্তর
45 years
সমাধান
Let, the unit's digit of woman's age be 'y' and ten's digit be 'x'
If so, the woman's age is = (10x + y) years and her husband’s age is = (10y + x) years. [Digits are reversed]
ATQ,
(10y + x) - (10x + y) = (10y + x) + (10x + y) (1/11)
or, 9y - 9x = (11y + 11x)/11
or, 9y - 9x = 11(y + x)/11
or, 9y - y = x + 9x
or, 10x = 8y
or, x = (4/5)y
Clearly, y should be a single digit and multiple of 5, which is 5 [only possible value]
Hence, y = 5 and x = 4
So, woman's age = (10x + y) = 45 years.
২২৩৮৪
A is 3 years older than C. B and D are twins. How older is c than D?
উত্তর
6 years
সমাধান
Given:A = B + 3 = C - 3B = D (they are twins)⇒ B + 3 = C - 3⇒ D + 3 = C - 3 ⇒ C = D + 6Therefore, C is 6 years older than D.
২২৩৮৫
In a garden , there are 10 rows and 12 columns of trees. The distance between any two trees is 2 m and a distance of 1 m is left from all sides of the boundary of the garden. What is the length of garden?
উত্তর
20 m
২২৩৮৬
In a cricket match , five batsmen A, B, C, D and E scored an average of 36 runs. D scored 5 more than E, E scored 8 fewer than A, B scored as many as D and E combined, and B and C jointly scored 107. How many runs did E score?
উত্তর
20
সমাধান
A+B+C+D+E = 36*5 = 180D = E+5 E = A-8 B = D+E = E+5+E = 2E+5B+C = 107 or, C = 107-B = 107-2E-5 = 102-2EE+8+2E+5+102-2E+E+5+E = 1803E = 180-120E = 60 (Ans.)
২২৩৮৭
At a dinner party , every two guests shared a bowl of rice between them , every three guests shared a bowl of vegetable among them and every four shared a bowl of meat among them. There were altogether 65 bowls. How many guests were present at the party?
উত্তর
60
সমাধান
Let the total number of guests be x. Then,
Number of bowls of rice = 2x
Number of bowls of dal = 3x
Number of bowls of meat = 4x
∴2x + 3x + 4x = 65
⟹126x + 4x + 3x = 65⟹1213x = 65⟹x = 60
Therefore, 60 guests were present at the party
২২৩৮৮
There are deer and peacocks in a zoo. The total number of their heads is 80 and the total number of their legs is 200. How many peacocks are there?
উত্তর
60
সমাধান
Let x and y be the number of deer and peacocks in the zoo respectively. Then,x + y = 80 ...(i) and4x + 2y = 200 or 2x + y = 100 ...(ii)Solving (i) and (ii), we get) x = 20, y = 60.
২২৩৮৯
A tailor had a number of shirt pieces to cut from some large pieces of fabric. He cut each large piece into 10 smaller pieces. He cut at the rate of 45 cuts per minute. How many large pieces would be cut in 24 minutes?
উত্তর
108
সমাধান
Number of cuts made to cut a large piece into 10 pieces = 9.
Therefore,
Required number of large pieces = (45 x 24)/9 = 120.
২২৩৯০
2 large and 1 small pumps can fill a water tank in 4 hours. 1 large and 3 small pumps can also fill the same water tank in 4 hours. How many hours will it take for 3 large 4 small pumps to fill the tank?
উত্তর
2 hours
সমাধান
Here, 2 large and 1 small pumps ≡ 1 large and 3 small pumps
Again, 3 large and 4 small pumps
= 2 large and 1 small pumps + 1 large and 3 small pumps
= 2 large and 1 small pumps + 2 large and 1 small pumps
= 2 x (2 large and 1 small pumps)
Now, 2 large and 1 small pumps can fill the tank in 4 hours
So, 2 x (2 large and 1 small pumps) can fill the tank = 4/2 = 2 hours