Brian has the same percentage of white stones and black stones in his collection of 100 stones as he does of grey stones and green stones in a separate collection. He has 40 grey stones and 60 green stones. How many white stones does Brian have if he has more white stones than black ones?

First we must determine the percentage of the grey and green stones. We add the two amounts together, finding 40+60=

<<40+60=100>>100 We then figure out that 40/100=<<40/100=.4>>.4, meaning 40 percent of the stones are grey in the second selection. This means that 1.0-.4= <<1.0-.4=.6>>.6, or 60 percent of the stones are green. Since there are more green stones than grey stones, and the white and black pile have the same percentage, and there are more white stones than black stones, that means there are 60 percent white stones in the first pile. Therefore, to find the number of white stones we multiply 100*.6= 60 white stones. #### 60 John had $200. He gave 3/8 of his money to his mother and 3/10 to his father. How much money did John have left? John's mother received 3/8 x $200 = $<<3/8*200=75>>75. His father got 3/10 x $200 = $<<3/10*200=60>>60. Thus, John gave a total of $75 + $60 = $<<75+60=135>>135. Therefore, John had $200 - $135 = $<<200-135=65>>65 left. #### 65 A book costs $4 more than a CD. The CD is 30% cheaper than a $20 album. How much does the book cost? The CD is 30/100 * 20 = $<<30/100*20=6>>6 cheaper than the album. So the cost of the CD is 20 - 6 = $<<20-6=14>>14. The book is $4 more expensive than the CD, which means it cost 14 + 4 = $<<14+4=18>>18. #### 18 A toy car factory made 60 cars yesterday. Today, they made twice the number of cars than yesterday. How many toy cars did the factory make? They made 60 x 2 = <<60*2=120>>120 cars today. So, the factory made a total of 60 + 120 = <<60+120=180>>180 cars. #### 180 Bea's mom planted 50 Mahogany and 30 Narra trees on their farm. Due to a typhoon, a total of 5 trees fell. One more Mahogany tree fell than the number of Narra trees that fell. A month after the typhoon, Bea's mom planted twice as much as the number of the Narra and thrice the number of Mahogany trees that fell. How many trees are now on the farm? Before the typhoon, their farm had a total of 50 trees + 30 trees = <<50+30=80>>80 trees. If there was 1 more than Mahogany than Narra tree that fell, then this means there were 2 Narra trees and 2 + 1 = 3 Mahogany trees that fell during the typhoon. So, Bea's mom planted 2 trees x 2 = <<2*2=4>>4 Narra trees. She also planted 3 trees x 3 = <<3*3=9>>9 Mahogany trees. So, her mom planted 4 trees + 9 trees = <<4+9=13>>13 more trees. After the typhoon, they only had 80 trees - 5 trees = <<80-5=75>>75 trees left. Therefore, there are 75 trees + 13 trees = <<75+13=88>>88 trees now. #### 88 Thomas is keeping track of the rainfall in May for his science project. On the first day, 26 cm of rain fell. On the second day, 34 cm fell. On the third day, 12 cm less than the second day fell. The average rainfall for the first three days of May is usually 140 cm across all three days, in a normal year. How much less is it raining this year than average? In total 26 + 34 + 22 = <<26+34+22=82>>82 cm fell for three days. If 140 cm is the average for the first three days, then 140 - 82 = <<140-82=58>>58 cm less than the average. #### 58 It’s spring! The gardener at Parc Municipal orders flowers. He takes 250 tulips, 375 carnations and 320 roses. Each flower is sold for 2€. Calculate the total expenses. First we calculate the number of flowers: 250 + 375 + 320 = <<250+375+320=945>>945€ Then the expense: 945 X 2 = <<945*2=1890>>1890€ So, the total expenditure is €<<1890=1890>>1890. #### 1890 The temperature in New York in June 2020 was 80 degrees. If the temperature in Miami on this day was 10 degrees hotter than the temperature in New York, and 25 degrees cooler than the temperature in San Diego, what was the average temperature for the three cities? If it was 10 degrees hotter on this day in Miami than in New York, then the temperature in Miami was 80+10 = 90 degrees. If it was 25 degrees cooler in Miami than in San Diego, then the temperature in San Diego was 90+25 = <<90+25=115>>115 degrees. The total temperature for all the cities is 115+90+80 = <<115+90+80=285>>285 degrees The average temperature of the three cities is 285/3 = <<285/3=95>>95 degrees #### 95 Alan bought a $2000 phone online. John bought it 2% more expensive in a local store. How much did John spend on his phone? The difference in price is 2% * 2000 = $<<2*.01*2000=40>>40 So, the price of John’s phone is 2000+40 = $<<2000+40=2040>>2040 #### 2040 Twice Angie's age, plus 4, is 20. How old is Angie? Twice Angie's age is 20-4=<<20-4=16>>16. Angie is 16/2=<<16/2=8>>8. #### 8