Given that 4a = 5b = 20, what is the value of 24ab?

Correct answer marked below

1,600

480

Correct

240

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Explanation

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Official Explanation

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Since 4a = 20, we can find that a = 5. Similarly, from 5b = 20, we find that b = 4.…

Comments

JonasApr 21

Thanks, this was a nice easy warmup. Took me like 30 seconds.

PranavSep 30

wait how do you get a and b from 4a = 20 and 5b = 20? I got a=5 and b=4 but then 24ab confused me for a sec lol

VasistOct 10

yeah just plug in, a=5 b=4, so ab=20 and then multiply. don't overthink it

PratikOct 1

same, I almost picked C because I divided somewhere. just be careful with the last step

GabrielJul 11

Is this really sub-505? Felt almost too straightforward. The "24ab" part is the only place people slip.

JawadJul 24

got it right but I initially thought the answer was A until I reread. tricky wording with the three equal signs.

What this question tests

Your ability to manipulate linear and quadratic expressions, substitute unknowns, and solve equations under time pressure.

Losing a sign when moving terms across the equals sign, or dividing both sides by a variable that could equal zero.