২১৪৬১
What is the minimum number of apples that must be added to the existing stock of 264 apples so that the total stock can be equally distributed amoung 6, 7 or 8 persons?
উত্তর
72
সমাধান
Since the apples need to be divided equally among 6, 7 or 8 people, first we calculate their LCM.
2/(6,7,8) = 3, 7, 4
:. LCM of 6, 7 or 8 = 2x3x7x4 = 168
The division produces a reminder 96. To make this remainder 0, the minimum no. of apples that must be added
= 168 - 96
= 72
Answer : 72
২১৪৬২
If 14 farmers can plough a field in three hours, how long will it take 15 farmers to do the same job?
উত্তর
168 minutes
সমাধান
Given, 14 farmers can plough a field in 3hours = (3 * 60) = 180 minutes
let, 15 farmers can do the same job in x minutes
ATQ,
14 * 180 = 15 * x
or, x = (14 * 180)/ 15
∴ x = 168
ans: 168 minutes
২১৪৬৩
একটি বৃত্তের ব্যাস তিন গুণ বৃদ্ধি পেলে ক্ষেত্রফল কতগুণ বৃদ্ধি পাবে?
উত্তর
৯ গুণ
সমাধান
বৃত্তের ব্যাস = ২r [r = ব্যাসার্ধ]
বৃত্তের ক্ষেত্রফল = πr২
ব্যাস ৩ গুন বৃদ্ধি হলে হবে ৬r এবং ব্যাসার্ধ = ৩r
ঐ বৃত্তের ক্ষেত্রফল = π(৩r)২ = ৯r২
৯ গুন বৃদ্ধি পাবে
২১৪৬৪
In a club 60% members are male and 70% members are graduates. Again, 50% of the graduate members are male. What percent of the club members are female and not graduate?
উত্তর
5%
সমাধান
Let, X be the percentage of female non - graduate members.
According to the question.
100 = 25 + 70 + X
(Male non - Graduates) (Graduates) (Female non - Graduate)
:. X = 100 - 95 = 5
ans: 5
২১৪৬৫
How many times does the digit '4' come to write numbers from 1 to 100?
উত্তর
19
সমাধান
The digit four appears once in each of the following: 4, 14, 24, 34, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 54, 64, 74, 84 and 94
4 comes 1 to 100 is 20 times
So, 4 comes 10 to 100 is (20 - 1) = 19 times
ans: for a total of 19 times.
২১৪৬৬
Sixty-five percent of a number is 21 less than; four-fifth of that number.What is the number?
উত্তর
140
সমাধান
Let, the number is x
65% of x is = 65x/100 = 13x/20
According to question,
13x/20 = 4x /5 - 21
4x/5 - 13x/20 = 21
(16x - 13x)/20 = 21
3x = 320
x = 140
২১৪৬৭
6 men or 8 women can do a work in 18 days. How many days will it require to complete the whole work if 3 men and 5 women work together?
উত্তর
16 days
সমাধান
shortcut method:
time required = (M1*W1*T) /(( M1*W2) + (M2*W1)
Here M for Men W for Women T for Time.
= (6*8*18)/((6*5) + (8*3))
= 16 days.
২১৪৬৮
Which of the following is the next number in the series: 2, 4, 3, 9, 4, 16, 5, 25, 6,-------?
উত্তর
36
সমাধান
2 * 2 = 4
3 * 3 = 9
4 * 4 = 16
5 * 5 = 25
So,6 * 6 = 36
Therefore, the series is 2, 4, 3, 9, 4, 16, 5, 25, 6, 36
২১৪৬৯
A sells an article which cost him TK.400 to B at a profit of 20%.B then sells it to C, making a profit 10% on the price he paid to A. How much does C pay B?
উত্তর
Tk528
সমাধান
Sells price of A = Cost price of B
Sells price of B = cost price of c
For, A
when Cost price 100 then sells price 120 tk
when cost price 1 then sells price 120/100 tk
when cost price 400 then sells price = (120×400)/100 = 480Tk.
For, B
when cost price 100 then sells price 110 Tk.
when cost price 480 then sells price = ( 110×480)/100 = 528Tk.
So, C will pay B Tk. 528
২১৪৭০
In a cash box, there are equal numbers of 10 paisa, 25 paisa and 50 paisa coins. If the box contains Tk. 170 in total of the three coin denominations, then what is the number of 10 paisa coins?
উত্তর
200
সমাধান
Let the number of 10 paisa coins be P.
Now, 170 TK = 17000 paisa
Then, 10P + 25P + 50P = 17000
or, 85P = 17000
or, P = 17000/85 = 200