What other compatible numbers could you use for 428 and 286

1 answer:

4 0

How about raising 286 up by 14 to 300 and compensating by lowering 428 by the same 14 Since I know that 14 + 14 is 28 then 28-14 is 14
So 428 - 14 = 414
So now I have 414 + 300 which I can do mentally - the answer is 714 and is also the answer to the original problem 428 + 286

Compensation works very well - bring one number up or down to a rounded number and compensate by doing the opposite to the other - instead of 199 + 457 - try 200 + 456
Same answer and because one of the numbers is nicely rounded, it is easy to add the other.

One more: 207 + 182 becomes 200 + 189 =389 I lowered one by 7 and raised the other one by the same 7.

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riadik2000 [5.3K]

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8 0

3 years ago

\250 doctors from three countries in Europe meeting in a conference to decide whether to approve a new vaccine for the flu. Amon

Bezzdna [24]

Answer:

0.683 = 68.3% probability that a randomly chosen doctor is in favor of the vaccine

Step-by-step explanation:

(a) What is the probability that a randomly chosen doctor is in favor of the vaccine

75% of 115/250 = 0.46(German).

60% of 65/250 = 0.26(French).

65% of 70/250 = 0.28(Englishmen). So

$p = 0.75*0.46 + 0.6*0.26 + 0.65*0.28 = 0.683$