Mean of 100 items is 49. It was discovered that three items which should have been 60, 70, 80 were wrongly read as 40, 20,50 respectively. The correct mean is

Question

Mean of 100 items is 49. It was discovered that three items which should have been 60, 70, 80 were wrongly read as 40, 20,50 respectively. The correct mean is (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Sum of 100 items = 49 × 100 = 4900 Sum of items added = 60 + 70 +80 = 210 Sum of items replaced = 40 +20 + 50 =110 New sum = 4900+ 210 -110 = 5000 ∴ Correct mean = (5000/100) = 50

Q. Mean of $100$ items is $49$ . It was discovered that three items which should have been $60, 70, 80$ were wrongly read as $40, 20, 50$ respectively. The correct mean is

Sum of $100$ items $= 49 \times 100 = 4900$
Sum of items added $= 60 + 70 + 80 = 210$
Sum of items replaced $= 40 + 20 + 50 = 110$
New sum $= 4900 + 210 - 110 = 5000$
$∴$ Correct mean $= \frac{5000}{100} = 50$

Q. Mean of 100 items is 49. It was discovered that three items which should have been 60,70,80 were wrongly read as 40,20,50 respectively. The correct mean is

Sum of 100 items =49×100=4900 Sum of items added =60+70+80=210 Sum of items replaced =40+20+50=110 New sum =4900+210−110=5000 ∴ Correct mean =1005000​=50

Q. Mean of $100$ items is $49$ . It was discovered that three items which should have been $60, 70, 80$ were wrongly read as $40, 20, 50$ respectively. The correct mean is

Sum of $100$ items $= 49 \times 100 = 4900$
Sum of items added $= 60 + 70 + 80 = 210$
Sum of items replaced $= 40 + 20 + 50 = 110$
New sum $= 4900 + 210 - 110 = 5000$
$∴$ Correct mean $= \frac{5000}{100} = 50$