Finding the Sum of Two Numbers When Their Product is 1,000

  • Thread starter Thread starter mustang
  • Start date Start date
  • Tags Tags
    List
AI Thread Summary
To find two whole numbers x and y such that their product is 1,000 and neither has 10 as a factor, it is determined that one number must end in 5 while the other must be even. This leads to the expressions x = 2a and y = 10b + 5, where a is a non-zero integer and b can be zero. By substituting these expressions into the product equation xy = 1,000, the problem can be simplified to find suitable values for a and b. The discussion emphasizes the necessity of these conditions to ensure the product meets the criteria. Ultimately, the solution involves solving the resulting equations to find the sum x + y.
mustang
Messages
169
Reaction score
0
If x and y are whole numbers that don't have10 as a factor, and if xy = 1,000, find x + y.
 
Physics news on Phys.org
You have 2 integers x and y such that their product xy is a multiple of 10, but neither x nor y is a multiple of 10 (the rightmost digit of the product is 0).

Then the rightmost digit of one of them, let's say y, must be 5, and then x must be an even number. Think about it and you will see that this is the only way to end up with 0 in the 1's column of the product.

So you can express x and y in a different form:
x = 2a
y = 10b + 5
where a is a non-zero integer and b is an integer (maybe 0).

Now, find the product in terms of a and b, set that equal to 1000 & see if that helps you find the answer.
 
Last edited:
The steps.

The answer with the steps to follow.
 
I edited my post. See hints above.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

How to Find x + y When xy = 1,000 Without Using 10 as a Factor?
Replies
3
Views
2K
Earthing of two parallel conducting plates
Replies
11
Views
1K
Understanding the Proper Uncertainty Formula to Use
Replies
4
Views
902
Diffrence between resolving vector to components and find projections
Replies
4
Views
1K
Projectile motion when kicking a ball that lands on an upward slope
Replies
13
Views
3K
"Tension: T1 vs T2 - What is Correct?
Replies
1
Views
2K
How to calculate freezing time for a moist food by-product (75% water)
Replies
6
Views
640
Find integer points on this equation
Replies
8
Views
1K
How to find the equilibrium position of three masses (two of them fixed)?
Replies
4
Views
2K
MHB Can you find the two numbers?
Replies
11
Views
3K

Hot Threads

Recent Insights

Back
Top