The average marks scored by Ganesh in English, Science, Mathematics and History is less than 15 from that scored by him in English, History, Geography and Mathematics. What is the difference of marks in Science and Geography scored by him?

Answer

To solve the problem, let's denote the marks scored by Ganesh in each subject as follows:

- Let \( E \) = Marks in English
- Let \( S \) = Marks in Science
- Let \( M \) = Marks in Mathematics
- Let \( H \) = Marks in History
- Let \( G \) = Marks in Geography

According to the problem, we have two average scores:

1. The average marks in English, Science, Mathematics, and History:
\[ \text{Average}_1 = \frac{E + S + M + H}{4} \]

2. The average marks in English, History, Geography, and Mathematics:
\[ \text{Average}_2 = \frac{E + H + G + M}{4} \]

The problem states that:
\[ \text{Average}_1 < \text{Average}_2 - 15 \]

Substituting the expressions for the averages, we get:
\[ \frac{E + S + M + H}{4} < \frac{E + H + G + M}{4} - 15 \]

To eliminate the fractions, we can multiply the entire inequality by 4:
\[ E + S + M + H < E + H + G + M - 60 \]

Now, we can simplify this inequality:
1. Cancel \( E \), \( H \), and \( M \) from both sides:
\[ S < G - 60 \]

This tells us that the marks in Science (S) are less than the marks in Geography (G) minus 60.

To find the difference between the marks in Science and Geography, we can rearrange the inequality:
\[ G - S > 60 \]

Thus, the difference between marks in Science and Geography is:
\[ G - S = D \quad \text{(where D is the difference)} \]
From the inequality, we know:
\[ D > 60 \]

### Conclusion:
The difference in marks between Science and Geography is greater than 60.