Follow the steps for 8
(1) 8 * 2 = 16
(2) 16 * 5 = 80
Note: you could just combine the first 2 steps and multiply by 10 to start with. Much easier: just add a 0 onto 8.
(3a) 12 * 8 = 96
(3b) 96 - 24 = 72
(3c) So you want to take 1/2 72 which is 36
(4) 36 + 80 = 116
Let's try this with x.
(2) x * 10 = 10x
(3) 1/2 (12*x - 24)
(3) 10x + 1/2 (12x - 24)
(3) 10x + 6x - 12
(4) 16x - 12
Problem B
Math wiz would add 12 to the number given to her and then divide by 16. That's pretty complicated to do quickly.
For example Let the original number be 1221
(2) Multiply by 10 12210
(3) Take 1/2 the difference between 12 times 1221 and 24 which is 1/2(14652 - 24) = 7314
And add this result to 12210
7314 + 12210 = 19524
Tell her the number. She has to add 12
19524 + 12 = 19536 And divide by 16
to get 1221.
Pretty complex even for a wizard.
Answer:
the probability that Jack draws the blue ball is 0.38539
Step-by-step explanation:
Given the data in the question;
box contains
blue balls = 5
red balls = 8
Jim and Jack start drawing balls from the box, respectively, one at a time, at random, and without replacement
Now,
on the first attempted;
⇒ ( 8/13) × ( 5/12) = 10/39
on the second attempt;
⇒ ( 8/13 ) ( 7/12) ( 6/11 ) ( 5/10 ) = 14/143
on the third attempt;
⇒ ( 8/13 ) ( 7/12) ( 6/11 ) ( 5/10 ) ( 4/9 ) ( 5/8 ) = 35/1287
on the fourth attempt;
⇒ ( 8/13 ) ( 7/12) ( 6/11 ) ( 5/10 ) ( 4/9 ) ( 3/8 ) ( 2/7 ) ( 5/6 ) = 5/1287
so we add everything;
⇒ 10/39 + 14/143 + 35/1287 + 5/1287
= 0.38539
Therefore, the probability that Jack draws the blue ball is 0.38539
M = 57+46
(Since she has 46 less then martha, you know to find how many martha has you have to add 46!)
M=103
So martha has 103 coins!
