Let the number be x.
So x-2 =15/x, or
x^2β2x-15=0, or
(x-5)(x+3)=0
Hence x = 5 or -3.
Check: When x=5, 5β2=3 which is 15/5=3.
When x=-3, -3β2=-5 which is 15/-3=-5.
The number is 5 or -3.
9 years
Bcz 3×3=9
5×3=15
7×3=21
Total = 45
Avg of this 45/3 = 15
if A is true B has to be true
To solve this problem, we can break it down into steps:
Step 1: Determine the individual rates of work for A, B, and C.
If A needs 8 days to finish the task, then their work rate is 1/8 of the task per day.
If B needs 12 days to finish the task, then their work rate is 1/12 of the task per day.
If C needs 16 days to finish the task, then their work rate is 1/16 of the task per day.
Step 2: Calculate the combined work rate of A and B.
If A works for 2 days, their contribution will be 2 * (1/8) = 1/4 of the task completed.
If B works until 25% of the job is left for C, then they will complete 75% of the task.
Step 3: Calculate the time it takes for B to complete 75% of the task.
Since B’s work rate is 1/12 of the task per day, it will take B (75%)/(1/12) = 9 days to complete 75% of the task.
Step 4: Calculate the remaining work for C.
If B completes 75% of the task, then the remaining work for C is 100% – 75% = 25% of the task.
Step 5: Calculate the time it takes for C to complete the remaining work.
Since C’s work rate is 1/16 of the task per day, it will take C (25%)/(1/16) = 4 days to complete the remaining 25% of the task.
Step 6: Calculate the total time required.
A worked for 2 days, B worked for 9 days, and C worked for 4 days, totaling 2 + 9 + 4 = 15 days.
Therefore, it will take a total of 15 days for A to work for 2 days, B to work until 25% of the job is left, and C to complete the remaining work.
2.88
Because 2 daughter should have same age
Let the age of the man be x
Then age of his son becomes (xβ24)
2 years later from now,
Age of man will be = x+2
and age of his son will be =(xβ24+2)=xβ22
According to question,
2(xβ22)=x+2
i.e., 2xβ44=x+2
i.e., x=46
Therefore ,
Present age of man=46 years
And present age of his son =46β24=22 years
16.8 sec
first 10 odd num are 1,3,5,7,9,11,13,15,17,19
sum=100
avg=100/10
avg of 10 odd num =10
240 m
2880, 480, 92, 24, 8, 4, 4
4×1 = 4
4×2=8
8×3=24
24×4= 96 (not 92)
96×5 =480
480×6= 2880
So answer is 92
Distance =speed Γtime
Speed =90kmph
90km take 60min time to reach
In 10min the distance covered =?
D=90Γ10/60
900/60
D=15
1. 1g
2. 3g with 1g counter
3. 3g
4. 3g plus 1g
5. 3g plus 1 g plus 1g weighed medicine
6. 9g with 3g counter
7. 9g with 1g of counter and 1g weighed medicine
8. 9g with 1g counter
9. 9g
10. 9g plus 1g
11. 9g plus 3g with 1g on counter
12. 9g plus 3g
13. All 3 weights on one side.
Answer: 66.67 km approx.
Solution:
Let the first train A move at u km/h.
Let the second train B move at v km/h.
Let the distance between two trains be d km
Let the speed of bee be b km/h
Therefore, the time taken by trains to collide = d/(u+v)
Now putting all the known values into the above equation, we get,
u = 50 km/hr
v = 70 km/hr
d = 100 km
b = 80 km/hr
Therfore, the total distance travelled by bee
= b*d/(u+v)
= 80 * 100/(50+70)
= 66.67 km (approx)
The definition of left and right depends on the observer and
is reversed when facing the opposite direction. The
definition of up and down does not depend on the orientation
of the observer.
Answer: 10
Reason:
The best case happens ONLY when each rat dies just as they
taste the FIRST bottle given to them (you can imagine it a
miracle π )
In this case, the very first 10 attempts reveal the
poisonous bottles. So the answer is 10.