২২৫৬১
Which of the following fractions is smaller than 8/9 and greater than 2/5?
উত্তর
3/7
২২৫৬২
If the sum of (8, 5 and x ) is 21, then the average of (8, 5 and x ) is -
উত্তর
7
সমাধান
According to question, 8 + 5 + x = 21or, x = 21 - 13so, x = 8So, the average is =8+5+83 or 213 or 7.
২২৫৬৩
Six years from now the combined age of father and son will be 54. If, currently , son is 5 times younger than his father then what is the present age of the father?
উত্তর
35
সমাধান
Let the present age of son and his father be S and 5S respectively. Six years from now, their ages will be (S + 6) and (5S + 6) respectively.
So, S + 6 + 5S + 6 = 54
or, 6S + 12 = 54
or, 6S = 54 - 12
or, 6S = 42
or, S = 42/6 = 7
So, present age of the father = 5 × 7 = 35 years
২২৫৬৪
A watermelon is divided into 18 equal pieces. If Naz takes 1/3 of the watermelon and Sarah takes 1/3 of the rest that are left, how many pieces are still left?
উত্তর
8
সমাধান
Naz takes = 1/3 of 18 = 6 pieces
Sarah takes = 1/3 of (18 - 6) = 1/3 of 12 = 4 pieces
Number of pieces left = 18 - (6 + 4) = 18 - 10 = 8 pieces
২২৫৬৫
Farhana has a cake recipe which states that the cake should be baked in a pan 8 inches in diameter. If farhana wants to use the recipe to make a cake of same depth but 12 inches in diameter,by what factor she should multiply the recipe ingredients?
উত্তর
2.25
সমাধান
Let the depth of the cake be h.
Volume of the smaller cake, π r2 h = π (8/2)2 × h = 16πh
Volume of the larger cake, π R2 h = π (12/2)2 × h = 36πh
So, ingredients should be multiplied by (36πh / 16πh) = 2.25
২২৫৬৬
If 3/p =6 and 3/q =15 then p -q =?
উত্তর
3/10
সমাধান
Here, 3/p = 6
or, p = 3/6 = 1/2
Again, 3/q = 15
or, q = 3/15 = 1/5
Now, p - q = 1/2 - 1/5 = 3/10
২২৫৬৭
A father is three times as old as his son. After fifteen years the father will be twice as old as his son's age at that time. Hence the father's present age is --
উত্তর
45
সমাধান
Let the present age of the father and his son be F and S respectively.
Now, F = 3S
Again, F + 15 = 2(S + 15)
or, 3S + 15 = 2S + 30
or, 3S - 2S = 30 - 15
or, S = 15
So, F = 3S = 3 × 15 = 45 years
২২৫৬৯
Two identical taps fill 2/5 of a tank in 20 minutes.when one of the taps goes dry n how many minutes will the remaining one tap fill the rest of the tank?
উত্তর
60 min
সমাধান
2 taps can fill in 20 minutes = 2/5th
1 tap can fill in 20 minutes = 1/5th.
remaining portion to be filled up = 1 - 2/5 = 3/5.
1/5th can be filled by 1 tap in 20 mins
3/5th can be filled by 1 tap in 20x3 mins = 60 minutes. (ans)
২২৫৭০
If a building "b' feet high casts a shadow 'f' feet long , then , at the same time of day, a tree 't' feet high will cast will cast a shadow how many feet long?
উত্তর
(ft)/b