Explanation

To find the marks obtained, multiply the fraction by the total marks:

Marks obtained = 3/5 × 100

= 3 × 20

= 60

Explanation

From Maryam's purchase:

4C + T = 1800

From Fatima's purchase:

6C + 2T = 3000

We can solve these equations using substitution or elimination. Let's use elimination.

Multiplying the first equation by 2:

8C + 2T = 3600

Now subtracting the second equation from this:

(8C + 2T) - (6C + 2T) = 3600 - 3000

2C = 600

C = 300

Explanation

First, find the consumption rate per person per day:

30 persons consume 20 kg in 25 days

Total consumption per day for 30 persons = 20 kg / 25 days = 0.8 kg/day

Consumption per person per day = 0.8 kg/day / 30 persons = 0.02667 kg/person/day

Now, find the consumption for 15 persons in 30 days:

Total consumption = 15 persons × 0.02667 kg/person/day × 30 days

= 15 × 0.8

= 12 kg

Explanation

When objects move in opposite directions, relative speed = sum of speeds.
=> 60 + 135 = 195 Kmph

Explanation

Let's denote the first number as x and the second number as y.

Given equations:

1. 2x + 3y = 61

2. 4x - 5y = 45

We can solve these equations using substitution or elimination. Let's use elimination.

Multiplying equation 1 by 2:

4x + 6y = 122

Now subtracting equation 2 from this:

(4x + 6y) - (4x - 5y) = 122 - 45

11y = 77

y = 7