Need help with a critical thinking algebra word problem?

Question

Reversible prime numbers. The prime number 13 has an interesting property, when its digits are reversed, the new number 31 is also prime. Find the sum of all prime numbers greater than 10 yet less than 125 that have this property. You must use algebra.

Answer 1

I'd be very interested to see how this problem can be worked out solely using algebra. Surely there must be some trial and error involved.

I can tell you this. A 2 digit prime + its reversible prime must be a multiple of 11. And all the sums must be even.

Answer 2

What do you mean by "you must use algebra"?
Do you want a sieve to find all primes between 10 and 125?
Anyway, here is a list of primes that answer your
question:
3 digit primes
113
107
101
2 digit pairs.
If a two digit prime fills the bill, its first digit
must be odd. Also if p is in the list, the
number with digits reversed will also be in the
list.
For example, 13 is in the list so its mate 31
also appears . So we only have to list
each applicable prime and its reverse except for
p = 11.
The 2 digit primes that work are
11
13 31
17 71
37 73
79 97
Finally, the sum of all the primes above is 750.

Answer 3

loosen up, do not panic. start up by ability of reviewing what you know approximately fractions, decimals and percents. Fractions are branch issues, decimals are fractions like a million/10 or a million/one hundred. in step with cents are in step with one hundred a million% = a million/one hundred or 2/2 hundred or any of that relatives of fractions. you're maximum suitable to *****, those are difficult issues till you quite comprehend the better ones. what's a 60% answer? If the entire, antifreeze plus water had a quantity of one hundred liters it may be 60 L AF and 40 L water. besides the undeniable fact that that's merely 30 L finished, so 60% of the 30L is AF or .6 x 30L combination = 18 L is AF and by ability of the comparable technique 40% of the 30L is water. .4 x 30 finished = 12 L water. you would be able to desire to renowned that previously you are able to go any extra. To make a mixture with extra % AF there could be extra AF. yet keep in mind once you upload ? Liters extra AF, that differences the entire of the aggregate. you would be able to desire to jot down and sparkling up an algebra problem. seventy 5% AF = ? + 18 ( the recent finished AF) / 30 + ? ( the recent finished combination) Use "x" extremely of "?" for the equation seventy 5/one hundred = (x + 18) / (x + 30) seventy 5/one hundred (x + 30) = (x + 18) sparkling up for x: seventy 5 (x + 30) = one hundred ( x + 18) x = 18 verify 30+18 = 40 8: 18 = 18 = 36 36/40 8 = .seventy 5 = seventy 5% It labored. i think of you're able to communicate on your instructor and with courtesy advise that he start up with extra handy issues till the class is familiar with what is going on.