n1+n2n1xˉ1+n2xˉ2=xˉ
70+3070⋅(54)+30(xˉ2)=60
⇒3780+30xˉ2=6000
∴xˉ2=306000−3780
=302220
=74
JEE Main 2015 — Mathematics Probability & Statistics
A factory is operating in two shifts, day and night, with 70 and 30 workers, respectively.If per day mean wage of the day shift workers is, ₹54 and per day mean wage of all the workers is ₹60, then per day mean wage of the night shift workers (in ₹) is :
Held on 10 Apr 2015 · Verified 6 Jul 2026.
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If the mean of the data <table class="pyq-table"><tbody><tr><th>Class</th><th>$5-10$</th><th>$10-15$</th><th>$15-20$</th><th>$20-25$</th><th>$25-30$</th><th>$30-35$</th></tr><tr><td>Frequency</td><td>$2$</td><td>$k$</td><td>$28$</td><td>$54$</td><td>$k+1$</td><td>$5$</td></tr></tbody></table> is $21$, then $k$ is one of the roots of the equation :
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Work through every JEE Main Probability & Statistics PYQ, year by year.