The month of January has 31 days, so from January 1st to February 14th, there are 31 + 14 or 45 days, namely x = 45.
y = 3.06 * sin[ 0.017(45) - 1.40 ] + 12.23.
make sure your calculator is in Degree mode.
5 pounds of banana = 5 x $0.8 = $4
5 pounds of apple = 5 x $ 1.4 = $7
total cost = $4 + $7 = $11
A number multiplied by a sum is the same as the sum of the number multiplied by each addend; a(b + c) = ab + ac
When you set up equations like this, look at the units for help. They cancel out during division and multiplication like numbers to give desired quantities. Rates can be reversed if need be (3 meters/sec or 1/3 sec/meter).
time × (distance / time) = distance
See.. time/time = 1; leaving distance
Subtract the rate of the opposing walkway...
t × (3 m/s - 1 m/s) = d
2t = d
Answer is then A.