SOLUTION: Mary and her brother John collect foreign coins. Mary has twice the number of coins that John has. Together they have 105 foreign coins. find how many coins Mary has.

Question 492909: Mary and her brother John collect foreign coins. Mary has twice the number of coins that John has. Together they have 105 foreign coins. find how many coins Mary has.

Answer by Maths68(1474) (Show Source): You can put this solution on YOUR website!
Let
John has = x coins
Mary has twice the number that John has = 2x
John's and Mary's coins together= 105
x+2x=105
3x=105
Divide by 3 both sides
3x/3=105/3
x=35
John has = x = 35 coins
Mary has twice the number that John has = 2x = 2*35=70

RELATED QUESTIONS
I'm having difficulty solving this problem, can you help me get started? Here goes: Mary (answered by stanbon)

sierra and her brother jarred collect foreign coins. Sierra has twice the number of coins (answered by josmiceli)

Mary has 1/3 of the money that Erin has. Erin has $8 less than John. Together they have... (answered by josgarithmetic)

mary has 30 coins made up of nickels and dimes. Together they are worth 2.40. How many... (answered by Maths68)

John gives smith as many coins Smith has. Smith then gives John as many coins as John... (answered by stanbon)

Mary has 84 coins that have a total value of 5.55$. if all the coins are nickels and... (answered by checkley71)

Mary has 15$ and John has 12$. Express the amount of money John has as a fraction of the... (answered by addingup)

Please help me solve this!: Mary has n dollars. John has $7 less than 3 times the... (answered by london maths tutor)

John has 36 coins that are nickels and dimes. If the value of the coins is $2.90, how... (answered by brucewill)