the rainfall this year was 18.6 cm. this is 3.2 cm less than half of the rainfall last year. what was the rainfall last year?
Its 43.6
let R = rainfall last year in cm.
18.6cm = (R/2) -3.2cm
21.8cm = R/2
R= ?
To find the rainfall last year, we need to solve the given equation:
Rainfall this year = 18.6 cm
Rainfall this year = (1/2) * Rainfall last year - 3.2 cm
Let's substitute the known values into the equation and solve for Rainfall last year:
18.6 cm = (1/2) * Rainfall last year - 3.2 cm
To isolate Rainfall last year, let's add 3.2 cm to both sides of the equation:
18.6 cm + 3.2 cm = (1/2) * Rainfall last year
21.8 cm = (1/2) * Rainfall last year
Now, to find Rainfall last year, we need to undo the multiplication by (1/2). We can do this by multiplying both sides of the equation by 2:
2 * 21.8 cm = 2 * (1/2) * Rainfall last year
43.6 cm = Rainfall last year
Therefore, the rainfall last year was 43.6 cm.