Question

The average per day rainfall for a 15-day period ar
al station is 125 mm per day. If every day from
the second day, there is an increase of 5 mm in the
rainfall over the previous day, what is the rainfalt on
the first day of this period?​

Answer 1

Answer:Annual rainfall averages 1100 mm, and dry season extends from November to April, accounting for only 10–20% of annual precipitation. Rainy season extends from May to October, and most precipitation is 6–8 for three months, accounting for about 60% of annual precipitation (Figure 2).

Step-by-step explanation:

Answer 2

Concept:

Average is the ratio of the sum of numbers to the total numbers.

Given:

The average per day rainfall for a 15-day = 125 mm per day

From the second day, there is an increase of 5 mm in the

rainfall over the previous day.

Find:  

We are asked to find out the rainfall on the first day.

Solution:

We have,

The average per day rainfall for a 15-day = 125 mm per day

So,

Total rainfall = 125 × 15 =  1875 mm,

NOw,

Using Arithmetic Progression,

Common difference (d) = 5,

So,

Sum of n terms  =  n/2 [2a + (n-1) d]

So,

1875 =  15/2 [2a + (15 - 1) × 5]

1875 = 15/2 [ 2a + 70]

3750 = 30a + 1050

⇒

30a = 2700

so, a = 90

i.e. Rainfall on first day = 90 mm

Hence we can say that the rainfall on the first day was 90 mm.

#SPJ3