Please help! How much is 840 miles in 3 & 1/2 hours?

I'm assuming your teacher wants you to calculate the speed

1/2 = 0.5

3 & 1/2 = 3 + 1/2 = 3 + 0.5 = 3.5

If a plane flies 840 miles in 3.5 hours, then,

speed = distance/time

speed = (840 mi)/(3.5 hr)

speed = (840/3.5) mph

speed = 240 mph

step-by-step explanation:

step-by-step explanation:

the original amount doesn't ''re just looking for the time it takes for 1/2 of the substance to we have

(1/2) =)     take the ln   of both sides

ln (1/2)   = )   and we can write

ln(1/2) = ) lne     and lne   = 1     so we have

ln(1/2) = -.1092t     divide both sides by -.1092

t = ln(1/2)/-.1092 = about 6.347 days = about 6.3 days (rounded)