Question

Janet and Jose are selling cupcakes for a school fundraiser. Janet sold 3 times as many cupcakes as Jose. Together they sold 28 cupcakes. How many cupcakes did Janet sell? How many cupcakes did Jose sell?

Answer 1

let us assume the number of cupcakes sold by Jose = x
Then
The number of cupcakes sold by Janet = 3x
Total number of cupcakes sold by Janet and Jose = 28
Then
x + 3x = 28
4x = 28
x = 28/4
   = 7
So
The number of cupcakes sold by Jose = 7
Then
The number of cupcakes sold by Janet = 3x
                                                                = 3 * 7
                                                                 = 21
So the number of cupcakes sold by Janet is 21 and the number of cupcakes sold by Jose is 7.

Answer 2

$\sf\ x\ is\ the\ most\ common\ variable\ used\ for\ an\ unknown\ value\ so\ let's\\say\ that\ Jose\ sold\ x\ cupcakes.\ That\ means\ that\ Janet\ sold\ 3x\ cupcakes.\\Together\ they\ sold\ 28\ cupcakes.\\\\3x+x=28\\\\4x=28\\\\x=7\\\\So\ Jose\ sold\ x = 7\ cupcakes\ and\ Janet\ sold\ 3x = 3\times7 = 21\ cupcakes.\\\\{\boxed{Jose=7}\\\\{\boxed{Janet=21}$