২২৫১১
A form sorting machine can sort 12 forms in 10 minutes. How many forms can it sort in one and half hours at this rate?
উত্তর
108
সমাধান
One and half hours = 90 minutes
The machine, in 10 minutes, can sort 12 forms
So, it, in 90 minutes, can sort 12 x 90 / 10 = 108 forms
২২৫১২
The average of 100 observations in a study was calculated as 49.7. Later it was revealed that one of the observations was misread as 64 instead of 94. What will be the correct average?
উত্তর
50
সমাধান
The erroneous total of the obsevations = 49.7 x 100 = 4970
The correct total of the observations = 4970 - 64 + 94 = 5000
So, the correct average = 5000/100 = 50.
২২৫১৩
If two planes leave the same airport at 1:00 p.m., how many miles apart will they be at 3:00 p.m. if one travels directly towards north at 150 miles per hour and the other travels directly towards west at 200 miles per hour?
উত্তর
500 miles
২২৫১৪
What is the sum of 134.679, -45.548 and -67.8807 rounded to the nearest tenths place?
উত্তর
21.3
সমাধান
Here, 134.679 - 45.548 - 67.8807 = 21.2503 ≈ 21.3
so,rounded to the nearest tenths place = 21.3
২২৫১৫
Farid can complete a job in 12 hours, and Jibon can complete the same job in 8 hours. Farid starts the job at 9 a.m., and stops working at 3 p.m. If Jibon starts working at 4 p.m. to complete the remaining job, at what time is the job finished?
উত্তর
8 p.m.
সমাধান
Farid works from 9 am to 3 pm = 6 hours
Farid can complete the job in 12 hours. So, in 6 hours, he can complete 6/12 or 1/2 of the job. Now, Jibon has to complete the rest 1/2 of the job. But, he can complete the job in 8 hours. So, he will take 8/2 or 4 hours only to complete the rest of the job. If Jibon starts working from 4 pm, the job will be completed by 8 pm.
২২৫১৬
What is the sum of 0.15, 0.10 and 0.65?
উত্তর
9/10
সমাধান
the sum of 0.15, 0.10 and 0.65
= 0.15 + 0.10 + 0.65
= 15/100 + 10/100 + 65/100
= 90/100
= 9/10(ans)
২২৫১৭
In his pocket, a boy has 3 red marbles, 4 blue marbles, and 4 green marbles. How many marbles will he have to take out of his pocket to ensure that he has taken out at least one of each color?
উত্তর
9
সমাধান
Even if he takes out all of the blue and green marbles (4 + 4 = 8), he still has one color left. So, to make sure that he has taken out atleast one marble of each colour, he will have to take (4 + 4 + 1 = 9) marbles out of his pocket.
২২৫১৮
If x=2y =3z and xyz =36 , what is the value of z?
উত্তর
root 2
সমাধান
Here., x = 2y = 3z
x = 3z
and, 2y = 3z
y = 3/2 z
xyz = 36
3z× 3/2 z × z = 36
9z3 = 72
z = 2
২২৫১৯
পিতা ও পুত্রের বয়সের অনুপাত ৭: ৩। চার বছর পূর্বে তাদের বয়সের অনুপাত ছিল ৩: ৫। বর্তমানে পুত্রের বয়স কত?
উত্তর
২৪ বছর
সমাধান
ধরি, পিতার বয়স = ৭ক
এবং, পুত্রের বয়স = ৩ক
( ৭ক - ৪) / (৩ক - ৪) = ১৩/৫
৩৫ক - ২০ = ৩৯ক - ৫২
৪ক = ৩২
ক = ৮
পুত্রের বয়স = ৩ × ৮ = ২৪
২২৫২০
If the value of X and Y in the fraction XZ/Y are both tripled, how does the value of the fraction change?
উত্তর
remains the same