if 50 apprentices can finish a job in 4 hours , and 30 journeymen can finish the same job in 6 hours , how much of the job should be completed by 10 apprentices and 15 journeymen in one hour ?
50 apprentices can finish the job in 4 hours , thus : 10 apprentices can finish the job in 4 * 5 = 20 hours ; in 1 hour 10 apprentices can finish 1 / 20 of the job . 30 journeymen can finish the same job in 4,5 hours , thus : 15 journeymen can finish the job in 6 * 2 = 12 hours ; in 1 hour 15 journeymen can finish 1 / 12 of the job . therefore , in 1 hour 10 apprentices and 15 journeymen can finish 1 / 20 + 1 / 12 = 2 / 15 of the job . answer : d .
add(divide(const_1, divide(multiply(50, 4), const_10)), divide(const_1, divide(multiply(30, 6), 15)))