Toy Cars=6 and total spending by Mr.Lee=$156
Explanation:
Let us first consider
Number of Airplanes=A Cars=C and Trains=T
Now how to start with the problem ? Just start reading it step by step. First statements says that The number of airplanes is 2/3 of The number of cars.
Now how to convert it into an mathematical expression?
here the word "=" is of most important, The number of airplanes "is" whenever you encountered "is" just place a "="
so the first statement can be converted into mathematical expression as,
A=2/3*C (The number of airplanes is 2/3 of The number of cars.)
Now as per the second condition we can write it in mathematical form as,
C=3/5*T (The number of cars is 3/5 the number of trains).
and the third condition as,
C=3/5*T (The number of cars is 3/5 the number of trains).
Now , we have expressed the statements in mathematical expressions. we have three expressions.
Now It is also given that total number of Toys=20 so we can write it as,
A+C+T=20. ............(1)
Till now we have expressed everything in the question in mathematical form.
now for solving such type of question we need to express the expression giving total in a single entity, expressed it in terms of Airplanes,Cars or Trains,
here we are expressing it in terms of Cars so we can rewrite it (1) as,
2/3*C+C+5/3*C=20 (A=2/3*C and C=3/5*T so T=5/3*C)
by solving this we will get C=6
Total number of car toys, answer of first part
now put this value of C in expression 1,
2/3*C+C+T=20
so the value of T will be 10. T=10
and the total is toys are 20 so 20-10+6=4
Means Airplanes are 4.
Now the cost for each toy is.
A=$12,C=$8 and T=1/2 A i.e T=$6.
So the total cost would be,
4*12+6*8+10*6=$156
$156 answer of second part
I Hope this will help you to solve such kind of Problems.