The ratio of Mollie’s age to Heather’s age is 4:9 Heather is 40 years older than Mollie How old is Mollie?

Megan and desmond each add the same amount of water to their aquarium megan makes 5 ml of chemical solution with every gallon of water for her aquarium desmond mixed 8 ml of chemical solution for every 2 gallon of the water for his aquarium.