Trevor asked his mother how old a tree is in my yard his mother says the sum of 10 and 2/3 of the trees age is in years is equal to (10+2/3)a =50, where A is the tree age in years. his equation is not correct. what error did he makea.the variable a should be mulitplied by 10 only and then added to 2/3b.the variable A should be multiplied by 2/3 only and then added to 10c.The variable A should be multiplied by 50, not by sum of 10 and 2/3d.c.The variable A should be multiplied by 2/3 and 50 and set equal to 10