Selena's family went on a trip. the total hotel bill was $659. the cost of the airfare was $633. use mental math to find the total cost for the hotel and the air fare.

This does not make sense

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.

Ithink it can be put them in order by 4 possible ways.that mean 3 group of 10 rocks,or an another group of 8 rocks.