The temperature has risen by a total of 7 degrees Celsius. Starting at -3°C and ending at +4°C, the difference between these two temperatures is 7°C. Thus, the temperature has increased by 7 degrees Celsius from last night to now.

To find the median of Alice's marks, first, arrange them in ascending order:
30, 54, 65, 85, 92
The median is the middle value in an ordered list. Since there are 5 numbers, the median is the third number:
Median = 65.

A = pi * r^2
r = d/2 = 8/2 = 4 cm
A = 3.14 * 4^2
A = 3.14 * 16
A = 50.24 cm^2

A change purse contains five coins, two 25 cents pieces and three 10 cents pieces. A coin is chosen at random from the purse. The probability of choosing a 10 cent piece is 30%.

Number of 10 cent pieces = 3
Total number of coins = 5

Probability = Number of 10 cent pieces / Total number of coins
Probability = 3 / 5
Probability = 0.6 or 60%

So, the probability of choosing a 10 cent piece is 60%.