Answer:
3/ 10
Step-by-step explanation:
Count of numbers up to 50 = 50
Prime numbers up to 50 :
{2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47}
Count of prime numbers up to 50 = 15
Hence, ratio of prime numbers to all numbers ;
15 : 50
3 / 10
y = 2x² + 18x + 36
Given
y = 2(x + 6)(x + 3) ← expand the factors using FOIL
y = 2(x² + 9x + 18) ← distribute parenthesis by 2
= 2x² + 18x + 36 ← in standard form
Based on the given variation, y does not vary directly with x and the constant of variation are 8, 3.2 and 1.25 respectively.
y = k × x
where,
k = constant of proportionality
y = -40
x = -5
-40 = k × -5
-40 = -5k
k = -40/-5
k = 8
when,
y = 8 and x = 2.5
8 = k × 2.5
8 = 2.5k
k = 8/2.5
k = 3.2
y = 5 and x = 4
5 = k × 4
5 = 4k
k = 5/4
k = 1.25
Learn more about variation:
brainly.com/question/6499629
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