There are 3 lighthouses along a strip of the coast. Lighthouse A shines its light on for 3 seconds and then off for 3 seconds. Lighthouse B shines its light on for 4 seconds and then off for 4 seconds. Lighthouse C shines its light on for 5 seconds and then off for 5 seconds. If all 3 lighthouses start shining their lights on at the same time when will be the next time all three lighthouses will shine their lights on at the same time?

Sum is 17 and their difference is 3

Some boys and girls were asked if they had a pet. one third of the group were boys. there were 20 boys. 20% of the girls had a pet. boys with a pet : girls with a pet = 1 : 5 i need to know how many girls there are.

(50 ) mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.