Answer:
- -3/13 ≈ -1/4
- -6/11 ≈ -1/2
- -7/9 ≈ -3/4
Step-by-step explanation:
We'll drop all the minus signs, since they don't contribute anything but distraction.
When numerators or denominators are relatively large, changing their value by 1 unit will have a relatively small effect on the value of the fraction. For example, ...
3/13 ≈ 3/12 = 1/4
If we compare the decimal values of these fractions, we see that ...
3/13 ≈ 0.230769... (6-digit repeating decimal)
The closest of the offered "reasonable estimate" fractions is 1/4 = 0.25.
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Likewise, 6/11 ≈ 6/12 = 1/2. In decimal, these fractions are ...
6/11 = 0.54... (2-digit repeat)
1/2 = 0.5
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We can also increase or decrease both numerator and denominator by the same amount to get a fraction with nearly the same value. This works best when the numbers are larger.
7/9 ≈ 6/8 = 3/4 . . . . . . both numerator and denominator decreased by 1
In decimal, these are ...
7/9 = 0.7... (1-digit repeat)
3/4 = 0.75
(23 x 2) - 12 = x
We need 2 cookies per student, so multiply the amount of students by 2. which is 23 x 2. Then because you already baked 12 subtract 12 from the original amount you needed to bake. Which is 46 - 12. Oh and if you wanted the answer, it's 34.
If my math is right it would be 730%
P(black) = 26/52 = 1/2
P(jack) = 4/52 = 1/13
so
P(black and jack) = (1/2)*(1/13) = 1/26
answer
P(black and jack) = 1/26
