Money problems. help ? -

i don t get these questions 1) carey has $2.55 made up of pennies, dimes and quarters. she has as many dimes as pennies and she has eighteen in coins in all. how many of each kind of coins does she have? 2) harry has $74.75. he earned $5 of his money by washing cars and the rest by mowing lawns. if he recieved $7.75 for each lawn that he mowed, how many lawns did he mow? 3) a piggy bank contains $4.40 in nickles, dimes and quarters. there are twice as many quarters as nickles, and five more dimes than nickles. how many of each is there?|::::|lt;lt; carey has $2.55 made up of pennies, dimes and quarters. she has as many dimes as pennies and she has eighteen in coins in all. how many of each kind of coins does she have? gt;gt; Let P = number of pennies D = number of dimes Q = number of quarters Equation 1 -- carey has $2.55 made up of pennies, dimes and quarters 0.01P + 0.10D + 0.25Q = 2.55 Equation 2 -- she has eighteen in coins in all P + D + Q = 18 Equation 3 -- she has as many dimes as pennies Since P = D, Equation 1 reduces to 0.01P + 0.10P + 0.25Q = 2.55 0.11P + 0.25Q = 2.55 --- call this Equation 4 and Equation 2 reduces to 2P + Q = 18 --- call this Equation 5 Consider Equations 4 and 5 at this point. You have two equations with two unknowns. I trust that you can solve simultaneous equations. lt;lt; harry has $74.75. he earned $5 of his money by washing cars and the rest by mowing lawns. if he recieved $7.75 for each lawn that he mowed, how many lawns did he mow? gt;gt; Let X = number of lawns mowed 5 + 7.75X = 74.75 7.75X = 74.75 - 5 7.75X = 69.75 X = 9 lawns lt;lt; a piggy bank contains $4.40 in nickles, dimes and quarters. there are twice as many quarters as nickles, and five more dimes than nickles. how many of each is there? gt;gt; Let N = numbe of nickels D = number of dimes Q = number of quarters Equation 1 -- a piggy bank contains $4.40 in nickles, dimes and quarters. 0.05N + 0.10D + 0.25Q = 4.40 . Equation 2 -- there are twice as many quarters as nickles, Q = 2N Equation 3 -- five more dimes than nickles. D = N + 5 lt;lt; how many of each is there? gt;gt; From here, given Equations 1, 2 and 3, I trust that you can proceed to solve the requirements on your own. Hope this helps.|::::|1) not sure cause I m Australian and don t know about pennies etc.. 2) $74.75 - $5.00 = ? divided by $7.75 = answer. 3) again don t not what nickles, pennies = etc...