২২৮৬১
In a sugar -water solution , the ratio of water to sugar is 8: 3. If you add 2 kgs of sugar, the ratio becomes 2:1 what was the amount of sugar in the original solution?
উত্তর
6
সমাধান
W : S = 8 : 3
W/S = 8/3
3W = 8S
Again, W/(s + 2) = 2/1
1W = 2s + 4
3W = 6S + 12
8S = 6S + 12
S = 6
২২৮৬২
Saurabh has purchased a square sheet of plywood of 196 square feet area. To cover a wall he must cut of 3 feet from a side. What is the area, in square feet, of the wall?
উত্তর
154
সমাধান
Side of the plywood = √196 = 14 feet
Shortest side of the wall = 14 - 3 = 11 feet
Area of the wall = 14×11 = 154 sq. ft
২২৮৬৩
The average of 6 number is 9 , when one number is discarded the average of the remaining numbers becomes 7.2. What is the discarded number?
উত্তর
18
সমাধান
Total of 6 number is 6×9 = 54
If 1 number is discarded then there are 5 numbers
So, total of 5 number is 5×7.2 = 36
So the discarded number is = ( 54 - 36) = 18
২২৮৬৪
In the figure below ACDH and BCEF are rectangles, AH=2, GH=3, GF=4, and FE=5. What is the area of BCDG?
উত্তর
10
২২৮৬৫
In a class composed of x girls and y boys what part of the class is composed of girls.
উত্তর
x / ( x +y)
সমাধান
No. of girls = x and no. of boys = y
So, total class = x + y
Part of the class composed of girls = x/(x + y)
২২৮৬৬
x = 2y +3 and y= -2 , Quantity A =x and Quantity B = -1
উত্তর
The two quantities are equal
সমাধান
x = 2y + 3 and y = - 2
So, x = 2 ( - 2) + 3
x = - 4 + 3
x = - 1
So, Quantity A = x = - 1 and B = - 1 are equal.
২২৮৬৭
If a and b are positive integers and (a -b) /3.5 - 4/7 , then
উত্তর
b< a
সমাধান
(a - b)/ 3.5 = 4/7
= 7 ( a - b) = 4×3.5
= a - b = 14/7
a - b = 2
So, a is greater than b.
২২৮৬৮
If n and p are both odd numbers , which of the following must be an even number?
উত্তর
n + p
সমাধান
Addition of two odd numbers always be an even number.
২২৮৬৯
If the length of a rectangle is increased by 20% and the width is decreased by 20%, the area is:
উত্তর
decreased by 4%
সমাধান
Let's assume the length of the rectangle is L and the width is W.Then the original area of the rectangle = L x WAfter the increase in length by 20%, the new length = L + 0.2L = 1.2LAfter the decrease in width by 20%, the new width = W - 0.2W = 0.8WSo, the new area of the rectangle = (1.2L) x (0.8W) = 0.96LWTherefore, the new area of the rectangle is 96% of the original area.Answer: 96% of the original area.decreased by 4%
২২৮৭০
If the price of apple is Tk. 80.00 a kilogram, and the price triples every 6 months, how long will it be untill the price of apple is Tk. 6480.00 a kilogram?
উত্তর
2 years
সমাধান
If the price of apple is Tk. 80.00 a kilogram, and the price triples every 6 monthsThen, every 6 months the price will be = 80 ×3= 240 After (6+6)=12 months it will be = 240×3 = 720After (12+6)=18 months it will be = 720×3= 2160After (18+6)=24 months it will be = 2160×3=6480So after 24 months or 2 years it Will be 6480 taka