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# [Smart Math] Algebra Problem 9

Here’s and example of a SMART MATH problem for ALGEBRA. A temporary worker engaged on a contract basis is paid $10 every day he attends work and$5 is deducted from his salary as a fine every day he remains absent. If in a month of 30 working days, he earns $240, for how many days was he absent from work that month? 1. 12 days 2. 5 days 3. 4 days 4. 3 days 5. 2 days ### The Usual Method [contentblock id=google-adsense-post] Let the number of days he remained absent be ‘x’. Hence, number of days he was present = (30 – x) Hence, $(30-x)\times 10-x\times 5=240$ $\therefore 300-10x-5x=240$ $\therefore 300-15x=240$ $\therefore 15x=60$ $\therefore x=4$days (Ans: 3) Estimated Time to arrive at the answer = 45 seconds. ### Using Technique [contentblock id=google-adsense-post] If the worker remained absent, he not only loses$5 but also loses the $10 daily wage. Thus the net loss for the worker is$15 (10 + 5).

Had the worker attended work on all 30 days, his earning would have been 30 x 10 = $300. But his actual earning =$240. Hence, the difference = 300 – 240 = $60 is attributable to the number of days he was absent. Since, loss per day of absence =$ 15, so for a loss of \$60, the worker was absent for 4 days.

(Ans: 3)

Estimated Time to arrive at the answer = 15 seconds.
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