The answer is 90%. You get this answer by multiplying both the numerator and denominator by 5 so 18x5=90 and 20x5=100 giving you a fraction of 90/100 and a percentage of 90%.
Take the decimal and multiply it by 100.
N = number of hours.
$5 per hour, total = 5*n = $5n
Since $35 has been saved.
The amount saved plus the amount got from baby sitting should be greater or equal to the $90 cost.
5n + 35 ≥ 90
5n ≥ 90 -35
5n ≥ 55
n ≥ 55/5
n ≥ 11
So Rodney should baby sit for at least 11 hours, that is 11 and above.
Multiples of 3
: 3, 6, 9, 12, 15, 18, 21, 24, ...
Multiples of 4
: 4, 8, 12, 16, 20, 24, ...
Multiples of 8
: 8, 16, 24, ..
2
Find the smallest number that is shared by all rows above. This is the LCM.
LCM = 2424
Method 2: By Prime Factors
1
List the prime factors of each number.
Prime Factors of 3
: 3
Prime Factors of 4
: 2, 2
Prime Factors of 8
: 2, 2, 2
2
Find the union of these primes.
2,2,2,32,2,2,3
3
Multiply these numbers: 2\times 2\times 2\times 3=242×2×2×3=24. This is the LCM.
LCM = 2424