To make it easier, lets say Justin = J, Eva = E, and Emma = M. Then, J = E + 7.50 M = J -12 J + E + M = 63 You can substitute for M in the third equation using the second equation, and you get: J + E + J - 12 = 63 Clean it up a little bit and you get: 2J + E = 75 You know J = E + 7.50, so substitute that for J and you get: 2(E + 7.50) + E = 75 2E + 15 + E = 75 3E + 15 = 75 3E = 60 E = 20 ; meaning that Eva has $20. Justin has $7.50 more than Eva, so he has $27.50. Emma has $12 less than Justin, so Emma has $15.50. Double check your answer by making sure they all add up to 63, which they do.
Answer:
There are two independent tests for a particular disease. The probability that Test! will fail to detect the disease in someone who has it is 0.30. The probability that Test II will fail to detect the disease that has it is 0.25. The probability that the disease will be undetected in someone who has it when both tests are applied is about : 75
42,812 and 62,812! You just add and subtract 10,000 from 52,812 and you will get the answer! Hope this helps!
(i) The simultaneous equations in a, b and c are a+b+c = 7 , 4a+2b+c = 9 & 9a+3b+c = 13
(ii) Expression for nth term = n²-n+7
The first three terms of the sequence are 7, 9, 13
nth term = an²+bn+c
If we put n = 1 then,
1st term = a(1)²+b+c
⇒ a+b+c = 7 ......(1)
If we put n = 2 then,
2nd term = a(2)²+b×2+c
⇒ 4a+2b+c = 9 ........(2)
3rd term = a(3)²+b×3+c
⇒ 9a+3b+c = 13 .......(3)
Multiplying 4 with (1) and subtract (2) from (1) we get,
(4a+4b+4c)-(4a+2b+c)=28-9
⇒ 4a+4b+4c-4a-2b-c=19
⇒ 2b+3c=19 .....(4)
Multiplying 9 with (1) and subtract (3) from (1) we get,
(9a+9b+9c)-(9a+3b+c)=63-13
⇒ 9a+9b+9c-9a-3b-c=50
⇒ 6b+8c=50
⇒ 3b+4c=25 .....(5)
Multiplying 3 with (4) and multiplying 2 with (5), then subtract (5) from (4),
3(2b+3c)-2(3b+4c)=57-50
⇒ 6b+9c-6b-8c=7
⇒ c = 7
From (5),
3b+28 = 25
⇒ 3b = -3
⇒ b = -1
From (1),
a+(-1)+7 = 7
⇒ a-1=0
⇒ a=1
So, nth term = n²-n+7
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Answer:
2, because there is 16 fluid ounces in a pint and 16+16= 32