Jo spent 40$ adn half of her remaing money. She then spent 29.45 and has 17.75 left. How much did she have?
The exercise is to match up the words with mathematical functions, and solve algebraically:
Let X = total money
"Jo spent 40": X -40
"and spent half of her remaining": -(1/2)(X-40)
"then spent 29.45": -29.45
(X - 40) -(1/2)(X-40) -29.45 = 17.75 "has 17.75 left"
X - 40 - (1/2)X + 20 - 29.45 = 17.75
(1/2)X -20 - 29.45 = 17.75
X = 2*(20+ 29.45 + 17.75)
X = $134.40