100 workers build the first floor of a seven-floor building in one month. Another 100 equally productive workers join them. How many months in total are needed to finish?
Intended model: all floors require equal work, rates stay constant, and the two groups’ rates add.
A worker makes a two-step staircase from 12 cubic blocks as shown. He covers all surfaces except the bottom with square tiles of side 15 cm. Find the total tile area in m².
Source clarification: the block side length is not explicitly stated. Use the intended model of one 15 cm square tile per cube face. The source asks for m² but prints the mixed-unit options below; retain them and compare by unit conversion.
A class has 40 students. Amy reports that 65% like ice cream; Ben says five eighths like chocolate; Claire says 75% like yogurt; Derek says two thirds like flan; Erik says 60% like cookies. Which student must be wrong?
Greg starts at 0 points. Each correct answer adds 5, each unanswered question adds 3, and each wrong answer adds 0. He finishes with 89 points. What is the least number of questions?
Mr Chris divides square land among five children as shown. Betty,Cindy,Dolly,Emma receive squares; Andy’s rectangle has perimeter 560 m. Find the perimeter of all the land.
A = Andy, B = Betty, C = Cindy, D = Dolly, E = Emma.
Andy and Billy repeatedly travel back and forth between home and the park, starting together at 06:45. Their speeds are 3 and 6 km/h. After departure, their second meeting is at 07:09. Find the one-way distance.
Intended model: they turn around immediately at each endpoint and maintain their speeds.
A solid made of identical stacked cubes has the top view and a view from one of its four sides as shown. What is its greatest possible number of cubes?
Aurora, Brenna, Clara, Donna, Erik, Freya, Gloria each enter one of Rooms 1, 2, 3 for interviews. Brenna says, “I was third to enter Room 1.” Clara says, “I was last to enter my room.” Erik says, “I was the only person in my room.” Freya says, “Three people, including Aurora, were already in the room when I entered.” Gloria says, “I was one of the two candidates taken to Room 2.” List the candidates in Room 1. Write the names in alphabetical order, separated by commas.