







The slope of a line 
20180222 

From Steve: my current slope is 6%. I want to know how many inches higher I will be at 18'
Thanks Answered by Penny Nom. 





2.5 gallons of liquid, one half an inch deep 
20180221 

From Cain: How many square feet would 2.5 gallons of liquid cover at half an inch deep? Answered by Penny Nom. 





nC0 + nC1 + nC2 + .... + nCn = 2^n 
20180219 

From bristal: (QQ) Prove, nC0 + nC1 + nC2 + .... + nCn = 2^n. Answered by Penny Nom. 





2 (a + 4) = 18 
20180218 

From rebecca: 2 (a + 4) = 18
how do i do this with showing it distributive property ( symbolically)
Thank you! Answered by Penny Nom. 





A footballer angle 
20180214 

From Kim: Two goal posts are 8m apart. A footballer is 34m from one post and 38m from the other. Within what angle must he kick the ball if he is to score a goal. Answered by Penny Nom. 





What is the speed of the skateboarder? 
20180213 

From Zack: It takes a skateboarder 20 minutes to get to school, which is 6 km from home. What is the speed of the skateboarder? Answered by Penny Nom. 





Solar cells 
20180212 

From karla: Solar (photovoltaic) cells convert sunlight directly into electricity. If solar cells were 100% efficient, they would generate about 1000 watts of power per square meter of surface area when exposed to direct sunlight. With lower efficiency, they generate proportionally less power. For example, 10% efficient cells generate 100 watts of power in direct sunlight. Suppose you want to supply 22 kilowattss of power to a house by putting solar panels on its roof. For solar cells with the average power of 49 watts per square meter of solar panels, how many square meters of solar panels would you need? Assume you can make use of the average power from the solar cells Answered by Penny Nom. 





Related rates 
20180211 

From angelo: hi admin please help me answer this question. thank you!
At a certain instant of time, the angle A of a triangle ABC is 60 degrees and increasing at the rate of 5degrees per second, the side AB is 10cm and increasing at the rate of 1cm per second, and side AC is 16cm and decreasing at the rate of 1/2 cm per second. Find the rate of change of side AB? Answered by Penny Nom. 





Water in a cone 
20180210 

From Shuvo: The diagram shows a vertical crosssection of a container in the form
of an inverted cone of height 60 cm and base radius 20 cm. The circular
base is held horizontal and uppermost. Water is pursed into the
container at a constant rate of 40 cm3/s.
Show that, when the depth of water in the container is x cm, the
volume of the water in the container is (πx^3)/27 cm3.
Find the rate of increase of "x" at the instant when "x" = 2. Answered by Penny Nom. 





3 yards 6 inches times 7 
20180208 

From Tamara: 3 yards 6 inches × 7 Answered by Penny Nom. 





A parallelogram, a rhombus and a rectangle 
20180207 

From Sambo: what do parallelogram, rhombus and rectangle have in common? Answered by Penny Nom. 





The wholesale price given the retail price and the markup 
20180207 

From Matthew: Retail $99
Markup is 80%
What is the equation to find the original (wholesale) price (55)?
thanks Answered by Penny Nom. 





Adding two negatives 
20180204 

From Pinasshakoane: (23)+(3) Answered by Penny Nom. 





A question about perfect squares 
20180204 

From Jolyn: Find the smallest possible value of a whole number m if 648x m is a perfect square Answered by Penny Nom. 





The code on a new phone 
20180202 

From Maria: Hi 
My husband gave me a new Samsung Galaxy mobile for out anniversaire gift. He set me a challenge which I have to solve before I can use the Phone. He has set the pin code with numbers 4, 7 and 0 and created a four digit code with the said numbers. Is there a way I can somehow list all possible combinations and try them all? Thanks! Answered by Penny Nom. 

