By creating a system of linear equations, the number of hours worked before they go to the movies is 10 hours.
Priya's earning :
Total earning, m = 8.40h - - - - (1)
Mai's Earning :
Total earning = 14 + 7h - - - - (2)
Equating (1) and (2) ;
8.40h = 14 + 7h
8.40h - 7h = 14
1.40h = 14
h = 14 ÷ 1.4
h = 10 hours
Therefore, they'll have to work for 10 hours
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