Subjects

Student makes a mathematical task for five minutes and the task from biology in twelve minutes. Another day he have homework in math and biology which consists of eleven tasks together. To do the job took hour and a half. How many tasks maked in each subject?

Correct result:

b =  5
m =  6

Solution:

5m+12b = 1.5•60
m+b=11

5•m+12•b = 1.5•60
m+b=11

12b+5m = 90
b+m = 11

b = 5
m = 6

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