8th Grade > Mathematics
DIRECT AND INVERSE PROPORTIONS MCQs
Total Questions : 58
| Page 2 of 6 pages
Answer: Option A. -> 750
:
A
Let n be the number of boxes.
As there are 12 crayons in each box, 2400 crayons fits into
240012=200boxes
Now the number of boxes produced will be directly proportional to time taken.
AB= Constant
A1B1 =A2B2
No.ofcrayonsboxestime=2004=n15
So, n = 750
:
A
Let n be the number of boxes.
As there are 12 crayons in each box, 2400 crayons fits into
240012=200boxes
Now the number of boxes produced will be directly proportional to time taken.
AB= Constant
A1B1 =A2B2
No.ofcrayonsboxestime=2004=n15
So, n = 750
Answer: Option B. -> 3,500
:
B
Let the required number of toys produced by 7 machines in 5 minutes be n.
As the time increases, the number of toys increases. Hence they are in direct proportion.
n = 490 x 5= 2450
So, 7 machines can make 2,450 toys in 5 minutes.
As the number of machines increases, number of toys increases. They are in direct proportion.
Let k is thenumber of toys produced by 10 machines in 5 minutes.
Then, k = 2450×107
⟹ k = 3500
So, the number of toys produced = 3,500
:
B
Let the required number of toys produced by 7 machines in 5 minutes be n.
As the time increases, the number of toys increases. Hence they are in direct proportion.
n = 490 x 5= 2450
So, 7 machines can make 2,450 toys in 5 minutes.
As the number of machines increases, number of toys increases. They are in direct proportion.
Let k is thenumber of toys produced by 10 machines in 5 minutes.
Then, k = 2450×107
⟹ k = 3500
So, the number of toys produced = 3,500
Answer: Option A. -> 15 days
:
A
Total number of work days required =10 x 20 = 200
Since 10 men worked for 10 days, 10 x 10 = 100 days work is already done.
So, 200 - 100 = 100 days of work is left.
Once, 10 more men joined, total number of workers=20
So, number of days required more =10020=5
Thus, total number of days = 10 + 5 = 15.
:
A
Total number of work days required =10 x 20 = 200
Since 10 men worked for 10 days, 10 x 10 = 100 days work is already done.
So, 200 - 100 = 100 days of work is left.
Once, 10 more men joined, total number of workers=20
So, number of days required more =10020=5
Thus, total number of days = 10 + 5 = 15.
Answer: Option D. -> 16 days
:
D
4 oxen = 12 cows
⇒ 1 ox = 124 cows
⇒7oxen≡124×7cows=21cows
⇒ (7 oxen + 3 cows) ≡ (21 cows + 3 cows) = 24 cows
Now, 12 cows can graze the field in 32 days.
So, 1 cow can graze the field in (32×12) days.
[less cows, more days]
24 cows can graze the field in 32×1224=16days
[more cows, less days]
Hence, 9 oxen and 3 cows can graze the field in 16 days.
:
D
4 oxen = 12 cows
⇒ 1 ox = 124 cows
⇒7oxen≡124×7cows=21cows
⇒ (7 oxen + 3 cows) ≡ (21 cows + 3 cows) = 24 cows
Now, 12 cows can graze the field in 32 days.
So, 1 cow can graze the field in (32×12) days.
[less cows, more days]
24 cows can graze the field in 32×1224=16days
[more cows, less days]
Hence, 9 oxen and 3 cows can graze the field in 16 days.
Answer: Option A. -> True
:
A
Numberofgifts3yPrice(InRupees)5501100
3550=y1100⇒y=3×1100550=6gifts
:
A
Numberofgifts3yPrice(InRupees)5501100
3550=y1100⇒y=3×1100550=6gifts
:
Remaining number of men = 250-50 =200 men
Remaining number of days = (350-25) days = 325 days.
250 men had provisions for 325 days
1 man had provisions for (250 × 325) days
200 men had provisions for (250×325)200 days
= 406.25days=406days
hence, the remaining food will last for 406 days.
:
Numberofbottles238yTime(Inhours)27
The time taken and the number of bottles filled are directly proportional.
AB= Constant
A1B1 =A2B2
2238=7y
⇒y=7×2382
⇒y=833bottles
Answer: Option B. -> 1 × 105
:
B
Weightofsugar125Numberofcrystals24×104y
This situation follows direct proportionality.
1224×104=5y
y=105
:
B
Weightofsugar125Numberofcrystals24×104y
This situation follows direct proportionality.
1224×104=5y
y=105