Answer:

Step-by-step explanation:
Given,
Red marbles = 3,
Green marbles = 10,
So, the total marbles = 3 + 10 = 13,

Since, here replacement is not allowed,
Thus, the probability of getting a green marble and a red marble
= first red and second green + first green second red




Note : The probability of getting a green marble first and a red marble second
= 


"Sum" tells us it's an addition problem:
One term is 12 and the other is 9/x
SO
The expression is:
12+9/x
Answer:
Therefore the area of the quadrilateral =35 cm²
Step-by-step explanation:
Given, the length of one of diagonal of quadrilateral is 10 cm and perpendicular drawn from the opposite vertices to this diagonal are the length of 2.8 cm and 4.2 cm.
A diagonal divided a quadrilateral into two triangle.
Therefore the area of the quadrilateral
= sum of the area of the triangles
cm² [ area of a triangle
]
=35 cm²