Stoplight a changes color every 30 seconds and stoplight b changes every 40 seconds. after how many seconds will the stoplights change colors at the same time again?

After 120 seconds

Step-by-step explanation:

Here, we want to know the number of seconds after which both spotlights will change colors at the same time again.

Basically, what we want to do here is to

calculate the value with which 30 and 40 have the same multiples or we want to

calculate the lowest common multiple of 30 and 40

The multiples of 30 are 30,60,90,120 etc

The multiples of 40 are 40,80,120 etc

We can see that the lowest common multiple of both is 120

So therefore the spotlights will change colors at the same time after 120 seconds

21 i watched a 3 hr vid explaining it

step-by-step explanation:

du what else would it be

brainliest

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation: