John earned $36 for 8 hours of work. Earnings are directly proportional with hours worked. How much did he earn when he worked 30 hours?

$135

Step-by-step explanation:

$36 / 8hrs = $4.5

$4.5 x 30hrs = 135

hope this helps :)

0.02

step-by-step explanation:

time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 k (but other seconds are sometimes used in astronomy)